21117524 has 12 divisors (see below), whose sum is σ = 37401504. Its totient is φ = 10431384.

The previous prime is 21117521. The next prime is 21117557. The reversal of 21117524 is 42571112.

It is a self number, because there is not a number n which added to its sum of digits gives 21117524.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21117521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31472 + ... + 32135.

It is an arithmetic number, because the mean of its divisors is an integer number (3116792).

Almost surely, 2^21117524 is an apocalyptic number.

It is an amenable number.

21117524 is a deficient number, since it is larger than the sum of its proper divisors (16283980).

21117524 is a wasteful number, since it uses less digits than its factorization.

21117524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63694 (or 63692 counting only the distinct ones).

The product of its digits is 560, while the sum is 23.

The square root of 21117524 is about 4595.3807241620. The cubic root of 21117524 is about 276.4061268794.

Adding to 21117524 its reverse (42571112), we get a palindrome (63688636).

The spelling of 21117524 in words is "twenty-one million, one hundred seventeen thousand, five hundred twenty-four".