22221520 has 40 divisors (see below), whose sum is σ = 52262280. Its totient is φ = 8785920.

The previous prime is 22221517. The next prime is 22221523. The reversal of 22221520 is 2512222.

It is an interprime number because it is at equal distance from previous prime (22221517) and next prime (22221523).

It can be written as a sum of positive squares in 4 ways, for example, as 1098304 + 21123216 = 1048^2 + 4596^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×22221520² = 987591902220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 22221494 and 22221503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22221523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5560 + ... + 8680.

It is an arithmetic number, because the mean of its divisors is an integer number (1306557).

Almost surely, 2^22221520 is an apocalyptic number.

22221520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22221520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26131140).

22221520 is an abundant number, since it is smaller than the sum of its proper divisors (30040760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

22221520 is a wasteful number, since it uses less digits than its factorization.

22221520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3223 (or 3217 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 22221520 is about 4713.9707254076. The cubic root of 22221520 is about 281.1412603503.

Adding to 22221520 its reverse (2512222), we get a palindrome (24733742).

The spelling of 22221520 in words is "twenty-two million, two hundred twenty-one thousand, five hundred twenty".