645139951874 has 16 divisors (see below), whose sum is σ = 1055700301536. Its totient is φ = 293240781600.

The previous prime is 645139951849. The next prime is 645139951903. The reversal of 645139951874 is 478159931546.

It is a happy number.

It is a super-2 number, since 2×645139951874² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1459694 + ... + 1849590.

It is an arithmetic number, because the mean of its divisors is an integer number (65981268846).

Almost surely, 2^645139951874 is an apocalyptic number.

645139951874 is a deficient number, since it is larger than the sum of its proper divisors (410560349662).

645139951874 is a wasteful number, since it uses less digits than its factorization.

645139951874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465121.

The product of its digits is 32659200, while the sum is 62.

The spelling of 645139951874 in words is "six hundred forty-five billion, one hundred thirty-nine million, nine hundred fifty-one thousand, eight hundred seventy-four".