640208817031 has 8 divisors (see below), whose sum is σ = 732556250624. Its totient is φ = 548083641240.

The previous prime is 640208817023. The next prime is 640208817047. The reversal of 640208817031 is 130718802046.

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

It is a cyclic number.

It is not a de Polignac number, because 640208817031 - 2³ = 640208817023 is a prime.

It is a super-2 number, since 2×640208817031² (a number of 24 digits) contains 22 as substring.

It is the 800131-st Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640208817091) by changing a digit.

It is a nontrivial repunit in base 800130.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55558275 + ... + 55569796.

It is an arithmetic number, because the mean of its divisors is an integer number (91569531328).

Almost surely, 2^640208817031 is an apocalyptic number.

640208817031 is a deficient number, since it is larger than the sum of its proper divisors (92347433593).

640208817031 is a wasteful number, since it uses less digits than its factorization.

640208817031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111128901.

The product of its (nonzero) digits is 64512, while the sum is 40.

The spelling of 640208817031 in words is "six hundred forty billion, two hundred eight million, eight hundred seventeen thousand, thirty-one".