640173688531 has 8 divisors (see below), whose sum is σ = 689552568320. Its totient is φ = 590814058752.

The previous prime is 640173688507. The next prime is 640173688537. The reversal of 640173688531 is 135886371046.

It is a happy number.

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 640173688531 - 2³¹ = 638026204883 is a prime.

It is a super-2 number, since 2×640173688531² (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 (640173688537) 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 7 ways as a sum of consecutive naturals, for example, 4743390 + ... + 4876483.

It is an arithmetic number, because the mean of its divisors is an integer number (86194071040).

Almost surely, 2^640173688531 is an apocalyptic number.

640173688531 is a deficient number, since it is larger than the sum of its proper divisors (49378879789).

640173688531 is a wasteful number, since it uses less digits than its factorization.

640173688531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9625005.

The product of its (nonzero) digits is 2903040, while the sum is 52.

The spelling of 640173688531 in words is "six hundred forty billion, one hundred seventy-three million, six hundred eighty-eight thousand, five hundred thirty-one".