21513036 has 12 divisors (see below), whose sum is σ = 50197112. Its totient is φ = 7171008.

The previous prime is 21513031. The next prime is 21513049. The reversal of 21513036 is 63031512.

It is a tau number, because it is divible by the number of its divisors (12).

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 in 3 ways as a sum of consecutive naturals, for example, 896365 + ... + 896388.

Almost surely, 2^21513036 is an apocalyptic number.

It is an amenable number.

21513036 is an abundant number, since it is smaller than the sum of its proper divisors (28684076).

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

21513036 is a wasteful number, since it uses less digits than its factorization.

21513036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1792760 (or 1792758 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21513036 is about 4638.2147427647. The cubic root of 21513036 is about 278.1210762566.

Adding to 21513036 its reverse (63031512), we get a palindrome (84544548).

The spelling of 21513036 in words is "twenty-one million, five hundred thirteen thousand, thirty-six".