20659644 has 48 divisors (see below), whose sum is σ = 53857440. Its totient is φ = 6848640.

The previous prime is 20659627. The next prime is 20659697. The reversal of 20659644 is 44695602.

20659644 is a `hidden beast` number, since 2 + 0 + 6 + 5 + 9 + 644 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20659599 and 20659608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24754 + ... + 25574.

It is an arithmetic number, because the mean of its divisors is an integer number (1122030).

Almost surely, 2^20659644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20659644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26928720).

20659644 is an abundant number, since it is smaller than the sum of its proper divisors (33197796).

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

20659644 is a wasteful number, since it uses less digits than its factorization.

20659644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1059 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 20659644 is about 4545.2881096802. The cubic root of 20659644 is about 274.3937897202.

The spelling of 20659644 in words is "twenty million, six hundred fifty-nine thousand, six hundred forty-four".