20981924 has 24 divisors (see below), whose sum is σ = 37459968. Its totient is φ = 10281600.

The previous prime is 20981899. The next prime is 20981929. The reversal of 20981924 is 42918902.

It is a super-2 number, since 2×20981924² = 880482269483552, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20981929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52124 + ... + 52524.

It is an arithmetic number, because the mean of its divisors is an integer number (1560832).

Almost surely, 2^20981924 is an apocalyptic number.

It is an amenable number.

20981924 is a deficient number, since it is larger than the sum of its proper divisors (16478044).

20981924 is a wasteful number, since it uses less digits than its factorization.

20981924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635 (or 633 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 20981924 is about 4580.6030170710. The cubic root of 20981924 is about 275.8132356872.

The spelling of 20981924 in words is "twenty million, nine hundred eighty-one thousand, nine hundred twenty-four".