645387972 has 48 divisors (see below), whose sum is σ = 1605273600. Its totient is φ = 201221280.

The previous prime is 645387971. The next prime is 645388031. The reversal of 645387972 is 279783546.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (645387971) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 97 + ... + 35927.

It is an arithmetic number, because the mean of its divisors is an integer number (33443200).

Almost surely, 2^645387972 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645387972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (802636800).

645387972 is an abundant number, since it is smaller than the sum of its proper divisors (959885628).

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

645387972 is a wasteful number, since it uses less digits than its factorization.

645387972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35936 (or 35934 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 51.

The square root of 645387972 is about 25404.4872414304. The cubic root of 645387972 is about 864.1854615159.

The spelling of 645387972 in words is "six hundred forty-five million, three hundred eighty-seven thousand, nine hundred seventy-two".