644473432 has 32 divisors (see below), whose sum is σ = 1273960800. Its totient is φ = 305040384.

The previous prime is 644473429. The next prime is 644473433. The reversal of 644473432 is 234374446.

It is a junction number, because it is equal to n+sod(n) for n = 644473391 and 644473400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644473433) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207 + ... + 35902.

It is an arithmetic number, because the mean of its divisors is an integer number (39811275).

Almost surely, 2^644473432 is an apocalyptic number.

It is an amenable number.

644473432 is a deficient number, since it is larger than the sum of its proper divisors (629487368).

644473432 is a wasteful number, since it uses less digits than its factorization.

644473432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36235 (or 36231 counting only the distinct ones).

The product of its digits is 193536, while the sum is 37.

The square root of 644473432 is about 25386.4812843371. The cubic root of 644473432 is about 863.7770736877. Note that the first 3 decimals are identical.

The spelling of 644473432 in words is "six hundred forty-four million, four hundred seventy-three thousand, four hundred thirty-two".