20645560 has 32 divisors (see below), whose sum is σ = 50027040. Its totient is φ = 7622784.

The previous prime is 20645551. The next prime is 20645561. The reversal of 20645560 is 6554602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19332 + ... + 20371.

It is an arithmetic number, because the mean of its divisors is an integer number (1563345).

Almost surely, 2^20645560 is an apocalyptic number.

20645560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20645560 is an abundant number, since it is smaller than the sum of its proper divisors (29381480).

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

20645560 is a wasteful number, since it uses less digits than its factorization.

20645560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39727 (or 39723 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 20645560 is about 4543.7385488164. The cubic root of 20645560 is about 274.3314227107.

The spelling of 20645560 in words is "twenty million, six hundred forty-five thousand, five hundred sixty".