645374572440 has 128 divisors (see below), whose sum is σ = 2194796217600. Its totient is φ = 150500298240.

The previous prime is 645374572393. The next prime is 645374572463. The reversal of 645374572440 is 44275473546.

It is a super-2 number, since 2×645374572440² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 10857246 + ... + 10916525.

It is an arithmetic number, because the mean of its divisors is an integer number (17146845450).

Almost surely, 2^645374572440 is an apocalyptic number.

645374572440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645374572440 is an abundant number, since it is smaller than the sum of its proper divisors (1549421645160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645374572440 is a wasteful number, since it uses less digits than its factorization.

645374572440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21773817 (or 21773813 counting only the distinct ones).

The product of its (nonzero) digits is 11289600, while the sum is 51.

The spelling of 645374572440 in words is "six hundred forty-five billion, three hundred seventy-four million, five hundred seventy-two thousand, four hundred forty".