644127660 has 96 divisors (see below), whose sum is σ = 2186150400. Its totient is φ = 156150720.

The previous prime is 644127629. The next prime is 644127697. The reversal of 644127660 is 66721446.

644127660 is a `hidden beast` number, since 644 + 1 + 2 + 7 + 6 + 6 + 0 = 666.

644127660 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 (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48280 + ... + 60159.

It is an arithmetic number, because the mean of its divisors is an integer number (22772400).

Almost surely, 2^644127660 is an apocalyptic number.

644127660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644127660 is an abundant number, since it is smaller than the sum of its proper divisors (1542022740).

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

644127660 is a wasteful number, since it uses less digits than its factorization.

644127660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108468 (or 108460 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 644127660 is about 25379.6702106233. The cubic root of 644127660 is about 863.6225685566.

The spelling of 644127660 in words is "six hundred forty-four million, one hundred twenty-seven thousand, six hundred sixty".