20565870 has 32 divisors (see below), whose sum is σ = 53155872. Its totient is φ = 5062272.

The previous prime is 20565863. The next prime is 20565871. The reversal of 20565870 is 7856502.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25977 + ... + 26756.

It is an arithmetic number, because the mean of its divisors is an integer number (1661121).

Almost surely, 2^20565870 is an apocalyptic number.

20565870 is an abundant number, since it is smaller than the sum of its proper divisors (32590002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20565870 is a wasteful number, since it uses less digits than its factorization.

20565870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52756.

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 20565870 is about 4534.9608598090. The cubic root of 20565870 is about 273.9780027450.

The spelling of 20565870 in words is "twenty million, five hundred sixty-five thousand, eight hundred seventy".