21797136 has 60 divisors (see below), whose sum is σ = 61360780. Its totient is φ = 7223040.

The previous prime is 21797131. The next prime is 21797159. The reversal of 21797136 is 63179712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18974736 + 2822400 = 4356^2 + 1680^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21797136.

It is not an unprimeable number, because it can be changed into a prime (21797131) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32646 + ... + 33306.

Almost surely, 2^21797136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21797136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30680390).

21797136 is an abundant number, since it is smaller than the sum of its proper divisors (39563644).

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

21797136 is a wasteful number, since it uses less digits than its factorization.

21797136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904 (or 895 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21797136 is about 4668.7403011947. The cubic root of 21797136 is about 279.3400101819.

The spelling of 21797136 in words is "twenty-one million, seven hundred ninety-seven thousand, one hundred thirty-six".