20565660 has 24 divisors (see below), whose sum is σ = 57584016. Its totient is φ = 5484160.

The previous prime is 20565659. The next prime is 20565667. The reversal of 20565660 is 6656502.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565667) 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, 171321 + ... + 171440.

It is an arithmetic number, because the mean of its divisors is an integer number (2399334).

Almost surely, 2^20565660 is an apocalyptic number.

20565660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20565660 is an abundant number, since it is smaller than the sum of its proper divisors (37018356).

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

20565660 is a wasteful number, since it uses less digits than its factorization.

20565660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342773 (or 342771 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 20565660 is about 4534.9377062976. The cubic root of 20565660 is about 273.9770702036.

The spelling of 20565660 in words is "twenty million, five hundred sixty-five thousand, six hundred sixty".