20645660 has 36 divisors (see below), whose sum is σ = 50436792. Its totient is φ = 7078176.

The previous prime is 20645579. The next prime is 20645671. The reversal of 20645660 is 6654602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9554 + ... + 11513.

It is an arithmetic number, because the mean of its divisors is an integer number (1401022).

Almost surely, 2^20645660 is an apocalyptic number.

20645660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20645660 is an abundant number, since it is smaller than the sum of its proper divisors (29791132).

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

20645660 is a wasteful number, since it uses less digits than its factorization.

20645660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21090 (or 21081 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 20645660 is about 4543.7495529573. The cubic root of 20645660 is about 274.3318656324.

The spelling of 20645660 in words is "twenty million, six hundred forty-five thousand, six hundred sixty".