642072405581 has 4 divisors (see below), whose sum is σ = 669988597152. Its totient is φ = 614156214012.

The previous prime is 642072405577. The next prime is 642072405593. The reversal of 642072405581 is 185504270246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 642072405581 - 2² = 642072405577 is a prime.

It is a super-2 number, since 2×642072405581² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642072405181) 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, 13958095751 + ... + 13958095796.

It is an arithmetic number, because the mean of its divisors is an integer number (167497149288).

Almost surely, 2^642072405581 is an apocalyptic number.

It is an amenable number.

642072405581 is a deficient number, since it is larger than the sum of its proper divisors (27916191571).

642072405581 is a wasteful number, since it uses less digits than its factorization.

642072405581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27916191570.

The product of its (nonzero) digits is 537600, while the sum is 44.

The spelling of 642072405581 in words is "six hundred forty-two billion, seventy-two million, four hundred five thousand, five hundred eighty-one".