644945532 has 48 divisors (see below), whose sum is σ = 1876207872. Its totient is φ = 167518080.

The previous prime is 644945527. The next prime is 644945549. The reversal of 644945532 is 235549446.

644945532 is digitally balanced in base 2, because in such base 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 (42).

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, 348073 + ... + 349920.

It is an arithmetic number, because the mean of its divisors is an integer number (39087664).

Almost surely, 2^644945532 is an apocalyptic number.

It is an amenable number.

644945532 is an abundant number, since it is smaller than the sum of its proper divisors (1231262340).

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

644945532 is a wasteful number, since it uses less digits than its factorization.

644945532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698018 (or 698016 counting only the distinct ones).

The product of its digits is 518400, while the sum is 42.

The square root of 644945532 is about 25395.7778380580. Note that the first 3 decimals coincide. The cubic root of 644945532 is about 863.9879381461.

The spelling of 644945532 in words is "six hundred forty-four million, nine hundred forty-five thousand, five hundred thirty-two".