220965816876561 has 81 divisors (see below), whose sum is σ = 347572276796563. Its totient is φ = 135244600642560.

The previous prime is 220965816876503. The next prime is 220965816876577. The reversal of 220965816876561 is 165678618569022.

The square root of 220965816876561 is 14864919.

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

220965816876561 is a `hidden beast` number, since 2 + 2 + 0 + 9 + 6 + 58 + 1 + 6 + 8 + 7 + 6 + 561 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 217821734676225 + 3144082200336 = 14758785^2 + 1773156^2 .

It is not a de Polignac number, because 220965816876561 - 2¹⁹ = 220965816352273 is a prime.

It is a super-2 number, since 2×220965816876561² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 220965816876561.

It is not an unprimeable number, because it can be changed into a prime (220965816871561) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 31082542075 + ... + 31082549183.

Almost surely, 2^{220965816876561} is an apocalyptic number.

220965816876561 is the 14864919-th square number.

220965816876561 is the 7432460-th centered octagonal number.

It is an amenable number.

220965816876561 is a deficient number, since it is larger than the sum of its proper divisors (126606459920002).

220965816876561 is an frugal number, since it uses more digits than its factorization.

220965816876561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14340 (or 7170 counting only the distinct ones).

The product of its (nonzero) digits is 522547200, while the sum is 72.

The spelling of 220965816876561 in words is "two hundred twenty trillion, nine hundred sixty-five billion, eight hundred sixteen million, eight hundred seventy-six thousand, five hundred sixty-one".