20940865 has 12 divisors (see below), whose sum is σ = 27621972. Its totient is φ = 15229280.

The previous prime is 20940859. The next prime is 20940877. The reversal of 20940865 is 56804902.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7683984 + 13256881 = 2772^2 + 3641^2 .

It is not a de Polignac number, because 20940865 - 2⁷ = 20940737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20940865.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 16702 + ... + 17911.

It is an arithmetic number, because the mean of its divisors is an integer number (2301831).

Almost surely, 2^20940865 is an apocalyptic number.

It is an amenable number.

20940865 is a deficient number, since it is larger than the sum of its proper divisors (6681107).

20940865 is a wasteful number, since it uses less digits than its factorization.

20940865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34640 (or 34629 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 20940865 is about 4576.1189888376. The cubic root of 20940865 is about 275.6332075411.

The spelling of 20940865 in words is "twenty million, nine hundred forty thousand, eight hundred sixty-five".