641975921842 has 4 divisors (see below), whose sum is σ = 962963882766. Its totient is φ = 320987960920.

The previous prime is 641975921813. The next prime is 641975921893. The reversal of 641975921842 is 248129579146.

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

It can be written as a sum of positive squares in only one way, i.e., 403010398561 + 238965523281 = 634831^2 + 488841^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160493980459 + ... + 160493980462.

Almost surely, 2^641975921842 is an apocalyptic number.

641975921842 is a deficient number, since it is larger than the sum of its proper divisors (320987960924).

641975921842 is a wasteful number, since it uses less digits than its factorization.

641975921842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320987960923.

The product of its digits is 8709120, while the sum is 58.

The spelling of 641975921842 in words is "six hundred forty-one billion, nine hundred seventy-five million, nine hundred twenty-one thousand, eight hundred forty-two".