644492160 has 512 divisors, whose sum is σ = 2604672000. Its totient is φ = 149299200.

The previous prime is 644492129. The next prime is 644492209. The reversal of 644492160 is 61294446.

644492160 is a `hidden beast` number, since 6 + 4 + 4 + 492 + 160 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4268085 + ... + 4268235.

It is an arithmetic number, because the mean of its divisors is an integer number (5087250).

Almost surely, 2^644492160 is an apocalyptic number.

644492160 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644492160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1302336000).

644492160 is an abundant number, since it is smaller than the sum of its proper divisors (1960179840).

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

644492160 is a wasteful number, since it uses less digits than its factorization.

644492160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 644492160 is about 25386.8501393930. The cubic root of 644492160 is about 863.7854405494.

It can be divided in two parts, 644 and 492160, that added together give a square (492804 = 702²).

The spelling of 644492160 in words is "six hundred forty-four million, four hundred ninety-two thousand, one hundred sixty".