642036810681 has 12 divisors (see below), whose sum is σ = 1059870290752. Its totient is φ = 366878177496.

The previous prime is 642036810673. The next prime is 642036810707. The reversal of 642036810681 is 186018630246.

It is not a de Polignac number, because 642036810681 - 2³ = 642036810673 is a prime.

It is a super-2 number, since 2×642036810681² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (642036810641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5095530181 + ... + 5095530306.

Almost surely, 2^642036810681 is an apocalyptic number.

It is an amenable number.

642036810681 is a deficient number, since it is larger than the sum of its proper divisors (417833480071).

642036810681 is a wasteful number, since it uses less digits than its factorization.

642036810681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10191060500 (or 10191060497 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

It can be divided in two parts, 64203 and 6810681, that added together give a square (6874884 = 2622²).

The spelling of 642036810681 in words is "six hundred forty-two billion, thirty-six million, eight hundred ten thousand, six hundred eighty-one".