20920815 has 32 divisors (see below), whose sum is σ = 38400000. Its totient is φ = 10795680.

The previous prime is 20920811. The next prime is 20920819. The reversal of 20920815 is 51802902.

It is an interprime number because it is at equal distance from previous prime (20920811) and next prime (20920819).

It is not a de Polignac number, because 20920815 - 2² = 20920811 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20920811) 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, 1686 + ... + 6684.

It is an arithmetic number, because the mean of its divisors is an integer number (1200000).

Almost surely, 2^20920815 is an apocalyptic number.

20920815 is a deficient number, since it is larger than the sum of its proper divisors (17479185).

20920815 is a wasteful number, since it uses less digits than its factorization.

20920815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5044 (or 5038 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 20920815 is about 4573.9277431984. The cubic root of 20920815 is about 275.5452103718.

The spelling of 20920815 in words is "twenty million, nine hundred twenty thousand, eight hundred fifteen".