20390856 has 32 divisors (see below), whose sum is σ = 52064640. Its totient is φ = 6651968.

The previous prime is 20390833. The next prime is 20390861. The reversal of 20390856 is 65809302.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7911 + ... + 10166.

It is an arithmetic number, because the mean of its divisors is an integer number (1627020).

Almost surely, 2^20390856 is an apocalyptic number.

It is an amenable number.

20390856 is an abundant number, since it is smaller than the sum of its proper divisors (31673784).

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

20390856 is a wasteful number, since it uses less digits than its factorization.

20390856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18133 (or 18129 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 20390856 is about 4515.6235449825. The cubic root of 20390856 is about 273.1986103210.

The spelling of 20390856 in words is "twenty million, three hundred ninety thousand, eight hundred fifty-six".