21717056 has 28 divisors (see below), whose sum is σ = 44584620. Its totient is φ = 10483200.

The previous prime is 21717043. The next prime is 21717061. The reversal of 21717056 is 65071712.

It can be written as a sum of positive squares in 2 ways, for example, as 14318656 + 7398400 = 3784^2 + 2720^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3995 + ... + 7706.

Almost surely, 2^21717056 is an apocalyptic number.

It is an amenable number.

21717056 is an abundant number, since it is smaller than the sum of its proper divisors (22867564).

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

21717056 is a wasteful number, since it uses less digits than its factorization.

21717056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11742 (or 11732 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 21717056 is about 4660.1562205574. The cubic root of 21717056 is about 278.9975034356.

Adding to 21717056 its reverse (65071712), we get a palindrome (86788768).

The spelling of 21717056 in words is "twenty-one million, seven hundred seventeen thousand, fifty-six".