644462400 has 84 divisors (see below), whose sum is σ = 2114389472. Its totient is φ = 171855360.

The previous prime is 644462393. The next prime is 644462417. The reversal of 644462400 is 4264446.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62332 + ... + 71931.

Almost surely, 2^644462400 is an apocalyptic number.

644462400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644462400 is an abundant number, since it is smaller than the sum of its proper divisors (1469927072).

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

644462400 is a wasteful number, since it uses less digits than its factorization.

644462400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134288 (or 134273 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The square root of 644462400 is about 25386.2640024089. The cubic root of 644462400 is about 863.7721449906.

The spelling of 644462400 in words is "six hundred forty-four million, four hundred sixty-two thousand, four hundred".