20915968 has 18 divisors (see below), whose sum is σ = 41750744. Its totient is φ = 10457856.

The previous prime is 20915963. The next prime is 20915969. The reversal of 20915968 is 86951902.

It is a self number, because there is not a number n which added to its sum of digits gives 20915968.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20915963) by changing a digit.

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 as a sum of consecutive naturals, namely, 40596 + ... + 41107.

Almost surely, 2^20915968 is an apocalyptic number.

It is an amenable number.

20915968 is a deficient number, since it is larger than the sum of its proper divisors (20834776).

20915968 is an frugal number, since it uses more digits than its factorization.

20915968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81719 (or 81705 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 20915968 is about 4573.3978615467. The cubic root of 20915968 is about 275.5239290021.

The spelling of 20915968 in words is "twenty million, nine hundred fifteen thousand, nine hundred sixty-eight".