20210664 has 16 divisors (see below), whose sum is σ = 50526720. Its totient is φ = 6736880.

The previous prime is 20210657. The next prime is 20210669. The reversal of 20210664 is 46601202.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20210664.

It is not an unprimeable number, because it can be changed into a prime (20210669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 421032 + ... + 421079.

It is an arithmetic number, because the mean of its divisors is an integer number (3157920).

Almost surely, 2^20210664 is an apocalyptic number.

20210664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20210664 is an abundant number, since it is smaller than the sum of its proper divisors (30316056).

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

20210664 is a wasteful number, since it uses less digits than its factorization.

20210664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842120 (or 842116 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 20210664 is about 4495.6272087441. The cubic root of 20210664 is about 272.3914850032.

Adding to 20210664 its reverse (46601202), we get a palindrome (66811866).

The spelling of 20210664 in words is "twenty million, two hundred ten thousand, six hundred sixty-four".