21012938 has 12 divisors (see below), whose sum is σ = 32951058. Its totient is φ = 10049160.

The previous prime is 21012913. The next prime is 21012991. The reversal of 21012938 is 83921012.

It can be written as a sum of positive squares in only one way, i.e., 20948929 + 64009 = 4577^2 + 253^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8873 + ... + 10988.

Almost surely, 2^21012938 is an apocalyptic number.

21012938 is a deficient number, since it is larger than the sum of its proper divisors (11938120).

21012938 is a wasteful number, since it uses less digits than its factorization.

21012938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19909 (or 19886 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21012938 is about 4583.9871291268. The cubic root of 21012938 is about 275.9490646746.

The spelling of 21012938 in words is "twenty-one million, twelve thousand, nine hundred thirty-eight".