642721738718 has 8 divisors (see below), whose sum is σ = 965028717720. Its totient is φ = 321045499480.

The previous prime is 642721738639. The next prime is 642721738753. The reversal of 642721738718 is 817837127246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157682393 + ... + 157686468.

It is an arithmetic number, because the mean of its divisors is an integer number (120628589715).

Almost surely, 2^642721738718 is an apocalyptic number.

642721738718 is a deficient number, since it is larger than the sum of its proper divisors (322306979002).

642721738718 is a wasteful number, since it uses less digits than its factorization.

642721738718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315369882.

The product of its digits is 6322176, while the sum is 56.

The spelling of 642721738718 in words is "six hundred forty-two billion, seven hundred twenty-one million, seven hundred thirty-eight thousand, seven hundred eighteen".