642717985681 has 8 divisors (see below), whose sum is σ = 681656710464. Its totient is φ = 604695466320.

The previous prime is 642717985639. The next prime is 642717985717. The reversal of 642717985681 is 186589717246.

642717985681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642717985681 is a prime.

It is a super-2 number, since 2×642717985681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642717985621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 229049911 + ... + 229052716.

It is an arithmetic number, because the mean of its divisors is an integer number (85207088808).

Almost surely, 2^642717985681 is an apocalyptic number.

642717985681 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

642717985681 is a deficient number, since it is larger than the sum of its proper divisors (38938724783).

642717985681 is a wasteful number, since it uses less digits than its factorization.

642717985681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458102711.

The product of its digits is 40642560, while the sum is 64.

The spelling of 642717985681 in words is "six hundred forty-two billion, seven hundred seventeen million, nine hundred eighty-five thousand, six hundred eighty-one".