20865939 has 4 divisors (see below), whose sum is σ = 27821256. Its totient is φ = 13910624.

The previous prime is 20865937. The next prime is 20865967. The reversal of 20865939 is 93956802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20865939 - 2¹ = 20865937 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20865939.

It is not an unprimeable number, because it can be changed into a prime (20865931) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3477654 + ... + 3477659.

It is an arithmetic number, because the mean of its divisors is an integer number (6955314).

Almost surely, 2^20865939 is an apocalyptic number.

20865939 is a deficient number, since it is larger than the sum of its proper divisors (6955317).

20865939 is an equidigital number, since it uses as much as digits as its factorization.

20865939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6955316.

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 20865939 is about 4567.9250212761. The cubic root of 20865939 is about 275.3040779706.

The spelling of 20865939 in words is "twenty million, eight hundred sixty-five thousand, nine hundred thirty-nine".