21311512 has 16 divisors (see below), whose sum is σ = 40713840. Its totient is φ = 10454496.

The previous prime is 21311503. The next prime is 21311527. The reversal of 21311512 is 21511312.

It is a super-2 number, since 2×21311512² = 908361087452288, which contains 22 as substring.

It is a congruent number.

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, 24708 + ... + 25555.

It is an arithmetic number, because the mean of its divisors is an integer number (2544615).

Almost surely, 2^21311512 is an apocalyptic number.

It is an amenable number.

21311512 is a deficient number, since it is larger than the sum of its proper divisors (19402328).

21311512 is a wasteful number, since it uses less digits than its factorization.

21311512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50322 (or 50318 counting only the distinct ones).

The product of its digits is 60, while the sum is 16.

The square root of 21311512 is about 4616.4393205153. The cubic root of 21311512 is about 277.2499145581.

Adding to 21311512 its reverse (21511312), we get a palindrome (42822824).

The spelling of 21311512 in words is "twenty-one million, three hundred eleven thousand, five hundred twelve".