20919968 has 12 divisors (see below), whose sum is σ = 41186250. Its totient is φ = 10459968.

The previous prime is 20919967. The next prime is 20920019. The reversal of 20919968 is 86991902.

It can be written as a sum of positive squares in only one way, i.e., 11751184 + 9168784 = 3428^2 + 3028^2 .

It is a super-2 number, since 2×20919968² = 875290122242048, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20919961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 326843 + ... + 326906.

Almost surely, 2^20919968 is an apocalyptic number.

It is an amenable number.

20919968 is a deficient number, since it is larger than the sum of its proper divisors (20266282).

20919968 is an equidigital number, since it uses as much as digits as its factorization.

20919968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653759 (or 653751 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 20919968 is about 4573.8351522546. The cubic root of 20919968 is about 275.5414917476.

The spelling of 20919968 in words is "twenty million, nine hundred nineteen thousand, nine hundred sixty-eight".