21660400235620 has 24 divisors (see below), whose sum is σ = 45682062996024. Its totient is φ = 8626974855936.

The previous prime is 21660400235569. The next prime is 21660400235651. The reversal of 21660400235620 is 2653200406612.

It can be written as a sum of positive squares in 4 ways, for example, as 49951356004 + 21610448879616 = 223498^2 + 4648704^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21660400235620.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2324072619 + ... + 2324081938.

It is an arithmetic number, because the mean of its divisors is an integer number (1903419291501).

Almost surely, 2^{21660400235620} is an apocalyptic number.

21660400235620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21660400235620 is an abundant number, since it is smaller than the sum of its proper divisors (24021662760404).

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

21660400235620 is a wasteful number, since it uses less digits than its factorization.

21660400235620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4648154799 (or 4648154797 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 37.

The spelling of 21660400235620 in words is "twenty-one trillion, six hundred sixty billion, four hundred million, two hundred thirty-five thousand, six hundred twenty".