22215440 has 80 divisors (see below), whose sum is σ = 57090096. Its totient is φ = 7987200.

The previous prime is 22215409. The next prime is 22215491. The reversal of 22215440 is 4451222.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 8317456 + 13897984 = 2884^2 + 3728^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42380 + ... + 42900.

Almost surely, 2^22215440 is an apocalyptic number.

22215440 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 22215440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28545048).

22215440 is an abundant number, since it is smaller than the sum of its proper divisors (34874656).

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

22215440 is a wasteful number, since it uses less digits than its factorization.

22215440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588 (or 582 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 22215440 is about 4713.3257897158. The cubic root of 22215440 is about 281.1156171182.

Adding to 22215440 its reverse (4451222), we get a palindrome (26666662).

The spelling of 22215440 in words is "twenty-two million, two hundred fifteen thousand, four hundred forty".