645616811952 has 640 divisors, whose sum is σ = 2360134656000. Its totient is φ = 164785259520.

The previous prime is 645616811921. The next prime is 645616811989. The reversal of 645616811952 is 259118616546.

It is a happy number.

645616811952 is a `hidden beast` number, since 6 + 4 + 5 + 616 + 8 + 1 + 19 + 5 + 2 = 666.

645616811952 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 71643127 + ... + 71652137.

It is an arithmetic number, because the mean of its divisors is an integer number (3687710400).

Almost surely, 2^645616811952 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 645616811952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1180067328000).

645616811952 is an abundant number, since it is smaller than the sum of its proper divisors (1714517844048).

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

645616811952 is a wasteful number, since it uses less digits than its factorization.

645616811952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9126 (or 9114 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

The spelling of 645616811952 in words is "six hundred forty-five billion, six hundred sixteen million, eight hundred eleven thousand, nine hundred fifty-two".