21513032 has 8 divisors (see below), whose sum is σ = 40336950. Its totient is φ = 10756512.

The previous prime is 21513031. The next prime is 21513049. The reversal of 21513032 is 23031512.

It can be written as a sum of positive squares in only one way, i.e., 21031396 + 481636 = 4586^2 + 694^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21513032.

It is not an unprimeable number, because it can be changed into a prime (21513031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1344557 + ... + 1344572.

Almost surely, 2^21513032 is an apocalyptic number.

It is an amenable number.

21513032 is a deficient number, since it is larger than the sum of its proper divisors (18823918).

21513032 is a wasteful number, since it uses less digits than its factorization.

21513032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2689135 (or 2689131 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21513032 is about 4638.2143115643. The cubic root of 21513032 is about 278.1210590192.

Adding to 21513032 its reverse (23031512), we get a palindrome (44544544).

The spelling of 21513032 in words is "twenty-one million, five hundred thirteen thousand, thirty-two".