642671640887 has 4 divisors (see below), whose sum is σ = 643900459080. Its totient is φ = 641442822696.

The previous prime is 642671640817. The next prime is 642671640929. The reversal of 642671640887 is 788046176246.

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

It is a cyclic number.

It is not a de Polignac number, because 642671640887 - 2²² = 642667446583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642671640817) 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, 614408312 + ... + 614409357.

It is an arithmetic number, because the mean of its divisors is an integer number (160975114770).

Almost surely, 2^642671640887 is an apocalyptic number.

642671640887 is a deficient number, since it is larger than the sum of its proper divisors (1228818193).

642671640887 is a wasteful number, since it uses less digits than its factorization.

642671640887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1228818192.

The product of its (nonzero) digits is 21676032, while the sum is 59.

The spelling of 642671640887 in words is "six hundred forty-two billion, six hundred seventy-one million, six hundred forty thousand, eight hundred eighty-seven".