20665684 has 48 divisors (see below), whose sum is σ = 41827968. Its totient is φ = 8857728.

The previous prime is 20665669. The next prime is 20665739. The reversal of 20665684 is 48656602.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44019 + ... + 44485.

It is an arithmetic number, because the mean of its divisors is an integer number (871416).

Almost surely, 2^20665684 is an apocalyptic number.

It is an amenable number.

20665684 is an abundant number, since it is smaller than the sum of its proper divisors (21162284).

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

20665684 is a wasteful number, since it uses less digits than its factorization.

20665684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544 (or 542 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 20665684 is about 4545.9524854534. The cubic root of 20665684 is about 274.4205274673.

It can be divided in two parts, 2066 and 5684, that added together give a triangular number (7750 = T₁₂₄).

The spelling of 20665684 in words is "twenty million, six hundred sixty-five thousand, six hundred eighty-four".