20911664 has 10 divisors (see below), whose sum is σ = 40516380. Its totient is φ = 10455824.

The previous prime is 20911651. The next prime is 20911673. The reversal of 20911664 is 46611902.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 653474 + ... + 653505.

It is an arithmetic number, because the mean of its divisors is an integer number (4051638).

Almost surely, 2^20911664 is an apocalyptic number.

It is an amenable number.

20911664 is a deficient number, since it is larger than the sum of its proper divisors (19604716).

20911664 is a wasteful number, since it uses less digits than its factorization.

20911664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306987 (or 1306981 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 20911664 is about 4572.9272900408. The cubic root of 20911664 is about 275.5050289869.

The spelling of 20911664 in words is "twenty million, nine hundred eleven thousand, six hundred sixty-four".