641517818887 has 4 divisors (see below), whose sum is σ = 699837620616. Its totient is φ = 583198017160.

The previous prime is 641517818881. The next prime is 641517818891. The reversal of 641517818887 is 788818715146.

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

It is not a de Polignac number, because 641517818887 - 2⁷ = 641517818759 is a prime.

It is a super-2 number, since 2×641517818887² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641517818881) 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, 29159900848 + ... + 29159900869.

It is an arithmetic number, because the mean of its divisors is an integer number (174959405154).

Almost surely, 2^641517818887 is an apocalyptic number.

641517818887 is a deficient number, since it is larger than the sum of its proper divisors (58319801729).

641517818887 is a wasteful number, since it uses less digits than its factorization.

641517818887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58319801728.

The product of its digits is 24084480, while the sum is 64.

The spelling of 641517818887 in words is "six hundred forty-one billion, five hundred seventeen million, eight hundred eighteen thousand, eight hundred eighty-seven".