642099318721 has 9 divisors (see below), whose sum is σ = 746938385571. Its totient is φ = 550366036752.

The previous prime is 642099318691. The next prime is 642099318733. The reversal of 642099318721 is 127813990246.

The square root of 642099318721 is 801311.

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

It can be written as a sum of positive squares in only one way, i.e., 496834668225 + 145264650496 = 704865^2 + 381136^2 .

It is not a de Polignac number, because 642099318721 - 2³³ = 633509384129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (642099318121) 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, 5551941 + ... + 5666413.

Almost surely, 2^642099318721 is an apocalyptic number.

642099318721 is the 801311-st square number.

642099318721 is the 400656-th centered octagonal number.

It is an amenable number.

642099318721 is a deficient number, since it is larger than the sum of its proper divisors (104839066850).

642099318721 is an frugal number, since it uses more digits than its factorization.

642099318721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228960 (or 114480 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 52.

The spelling of 642099318721 in words is "six hundred forty-two billion, ninety-nine million, three hundred eighteen thousand, seven hundred twenty-one".