21078964 has 12 divisors (see below), whose sum is σ = 36956164. Its totient is φ = 10520064.

The previous prime is 21078949. The next prime is 21078991. The reversal of 21078964 is 46987012.

It can be written as a sum of positive squares in 2 ways, for example, as 19536400 + 1542564 = 4420^2 + 1242^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2259 + ... + 6874.

Almost surely, 2^21078964 is an apocalyptic number.

It is an amenable number.

21078964 is a deficient number, since it is larger than the sum of its proper divisors (15877200).

21078964 is a wasteful number, since it uses less digits than its factorization.

21078964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9714 (or 9712 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21078964 is about 4591.1832897413. The cubic root of 21078964 is about 276.2377877937.

The spelling of 21078964 in words is "twenty-one million, seventy-eight thousand, nine hundred sixty-four".