20671864 has 32 divisors (see below), whose sum is σ = 41489280. Its totient is φ = 9621504.

The previous prime is 20671817. The next prime is 20671873. The reversal of 20671864 is 46817602.

It is a super-2 number, since 2×20671864² = 854651922468992, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent 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, 12409 + ... + 13975.

It is an arithmetic number, because the mean of its divisors is an integer number (1296540).

Almost surely, 2^20671864 is an apocalyptic number.

It is an amenable number.

20671864 is an abundant number, since it is smaller than the sum of its proper divisors (20817416).

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

20671864 is a wasteful number, since it uses less digits than its factorization.

20671864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1687 (or 1683 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20671864 is about 4546.6321601819. The cubic root of 20671864 is about 274.4478795716.

The spelling of 20671864 in words is "twenty million, six hundred seventy-one thousand, eight hundred sixty-four".