20221440 has 80 divisors (see below), whose sum is σ = 64669968. Its totient is φ = 5390336.

The previous prime is 20221433. The next prime is 20221441. The reversal of 20221440 is 4412202.

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 (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20221441) 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, 6364 + ... + 8996.

Almost surely, 2^20221440 is an apocalyptic number.

20221440 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 20221440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32334984).

20221440 is an abundant number, since it is smaller than the sum of its proper divisors (44448528).

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

20221440 is an equidigital number, since it uses as much as digits as its factorization.

20221440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2659 (or 2643 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 20221440 is about 4496.8255469831. The cubic root of 20221440 is about 272.4398879835.

Adding to 20221440 its reverse (4412202), we get a palindrome (24633642).

The spelling of 20221440 in words is "twenty million, two hundred twenty-one thousand, four hundred forty".