20561400601660 has 12 divisors (see below), whose sum is σ = 43178941263528. Its totient is φ = 8224560240656.

The previous prime is 20561400601657. The next prime is 20561400601661. The reversal of 20561400601660 is 6610600416502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561400601661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 514035015022 + ... + 514035015061.

It is an arithmetic number, because the mean of its divisors is an integer number (3598245105294).

Almost surely, 2^{20561400601660} is an apocalyptic number.

20561400601660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20561400601660 is an abundant number, since it is smaller than the sum of its proper divisors (22617540661868).

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

20561400601660 is a wasteful number, since it uses less digits than its factorization.

20561400601660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1028070030092 (or 1028070030090 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 20561400601660 in words is "twenty trillion, five hundred sixty-one billion, four hundred million, six hundred one thousand, six hundred sixty".