642465386081 has 4 divisors (see below), whose sum is σ = 642469327812. Its totient is φ = 642461444352.

The previous prime is 642465385943. The next prime is 642465386089. The reversal of 642465386081 is 180683564246.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 312834387856 + 329630998225 = 559316^2 + 574135^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642465386081 is a prime.

It is a super-2 number, since 2×642465386081² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642465386089) 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, 1715336 + ... + 2056041.

It is an arithmetic number, because the mean of its divisors is an integer number (160617331953).

Almost surely, 2^642465386081 is an apocalyptic number.

It is an amenable number.

642465386081 is a deficient number, since it is larger than the sum of its proper divisors (3941731).

642465386081 is a wasteful number, since it uses less digits than its factorization.

642465386081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3941730.

The product of its (nonzero) digits is 6635520, while the sum is 53.

The spelling of 642465386081 in words is "six hundred forty-two billion, four hundred sixty-five million, three hundred eighty-six thousand, eighty-one".