642612016645 has 4 divisors (see below), whose sum is σ = 771134419980. Its totient is φ = 514089613312.

The previous prime is 642612016633. The next prime is 642612016679. The reversal of 642612016645 is 546610216246.

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 199516768929 + 443095247716 = 446673^2 + 665654^2 .

It is a cyclic number.

It is not a de Polignac number, because 642612016645 - 2²¹ = 642609919493 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64261201660 + ... + 64261201669.

It is an arithmetic number, because the mean of its divisors is an integer number (192783604995).

Almost surely, 2^642612016645 is an apocalyptic number.

It is an amenable number.

642612016645 is a deficient number, since it is larger than the sum of its proper divisors (128522403335).

642612016645 is a wasteful number, since it uses less digits than its factorization.

642612016645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128522403334.

The product of its (nonzero) digits is 414720, while the sum is 43.

The spelling of 642612016645 in words is "six hundred forty-two billion, six hundred twelve million, sixteen thousand, six hundred forty-five".