20864865 has 32 divisors (see below), whose sum is σ = 40400640. Its totient is φ = 8976384.

The previous prime is 20864863. The next prime is 20864923. The reversal of 20864865 is 56846802.

It is not a de Polignac number, because 20864865 - 2¹ = 20864863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20864863) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4060 + ... + 7629.

It is an arithmetic number, because the mean of its divisors is an integer number (1262520).

Almost surely, 2^20864865 is an apocalyptic number.

It is an amenable number.

20864865 is a deficient number, since it is larger than the sum of its proper divisors (19535775).

20864865 is a wasteful number, since it uses less digits than its factorization.

20864865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11721.

The product of its (nonzero) digits is 92160, while the sum is 39.

The square root of 20864865 is about 4567.8074609160. The cubic root of 20864865 is about 275.2993544567.

The spelling of 20864865 in words is "twenty million, eight hundred sixty-four thousand, eight hundred sixty-five".