645064531615 has 32 divisors (see below), whose sum is σ = 885951250560. Its totient is φ = 441684762624.

The previous prime is 645064531613. The next prime is 645064531663. The reversal of 645064531615 is 516135460546.

It is a happy number.

It is not a de Polignac number, because 645064531615 - 2¹ = 645064531613 is a prime.

It is a super-2 number, since 2×645064531615² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645064531613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 147508569 + ... + 147512941.

It is an arithmetic number, because the mean of its divisors is an integer number (27685976580).

Almost surely, 2^645064531615 is an apocalyptic number.

645064531615 is a deficient number, since it is larger than the sum of its proper divisors (240886718945).

645064531615 is a wasteful number, since it uses less digits than its factorization.

645064531615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9571.

The product of its (nonzero) digits is 1296000, while the sum is 46.

The spelling of 645064531615 in words is "six hundred forty-five billion, sixty-four million, five hundred thirty-one thousand, six hundred fifteen".