20185799965321 has 9 divisors (see below), whose sum is σ = 20858103715149. Its totient is φ = 19534510341900.

The previous prime is 20185799965271. The next prime is 20185799965339. The reversal of 20185799965321 is 12356999758102.

The square root of 20185799965321 is 4492861.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 20185799965321 - 2⁹ = 20185799964809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20185799965921) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 139206226 + ... + 139351156.

It is an arithmetic number, because the mean of its divisors is an integer number (2317567079461).

Almost surely, 2^{20185799965321} is an apocalyptic number.

20185799965321 is the 4492861-st square number.

20185799965321 is the 2246431-st centered octagonal number.

It is an amenable number.

20185799965321 is a deficient number, since it is larger than the sum of its proper divisors (672303749828).

20185799965321 is an frugal number, since it uses more digits than its factorization.

20185799965321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289924 (or 144962 counting only the distinct ones).

The product of its (nonzero) digits is 73483200, while the sum is 67.

The spelling of 20185799965321 in words is "twenty trillion, one hundred eighty-five billion, seven hundred ninety-nine million, nine hundred sixty-five thousand, three hundred twenty-one".