20445864 has 32 divisors (see below), whose sum is σ = 52765440. Its totient is φ = 6595200.

The previous prime is 20445851. The next prime is 20445869. The reversal of 20445864 is 46854402.

It is not an unprimeable number, because it can be changed into a prime (20445869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12997 + ... + 14484.

It is an arithmetic number, because the mean of its divisors is an integer number (1648920).

Almost surely, 2^20445864 is an apocalyptic number.

20445864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20445864 is an abundant number, since it is smaller than the sum of its proper divisors (32319576).

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

20445864 is a wasteful number, since it uses less digits than its factorization.

20445864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27521 (or 27517 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 33.

The square root of 20445864 is about 4521.7102958947. The cubic root of 20445864 is about 273.4440571968. Note that the first 3 decimals are identical.

The spelling of 20445864 in words is "twenty million, four hundred forty-five thousand, eight hundred sixty-four".