645123072 has 176 divisors, whose sum is σ = 1987915392. Its totient is φ = 183828480.

The previous prime is 645123029. The next prime is 645123091. The reversal of 645123072 is 270321546.

It is a tau number, because it is divible by the number of its divisors (176).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 573903 + ... + 575025.

Almost surely, 2^645123072 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 645123072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (993957696).

645123072 is an abundant number, since it is smaller than the sum of its proper divisors (1342792320).

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

645123072 is a wasteful number, since it uses less digits than its factorization.

645123072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1174 (or 1156 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 645123072 is about 25399.2730604638. The cubic root of 645123072 is about 864.0672101351.

The spelling of 645123072 in words is "six hundred forty-five million, one hundred twenty-three thousand, seventy-two".