644125158 has 12 divisors (see below), whose sum is σ = 1395604548. Its totient is φ = 214708380.

The previous prime is 644125151. The next prime is 644125159. The reversal of 644125158 is 851521446.

It is a happy number.

644125158 is a `hidden beast` number, since 644 + 1 + 2 + 5 + 1 + 5 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644125151) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17892348 + ... + 17892383.

It is an arithmetic number, because the mean of its divisors is an integer number (116300379).

Almost surely, 2^644125158 is an apocalyptic number.

644125158 is an abundant number, since it is smaller than the sum of its proper divisors (751479390).

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

644125158 is a wasteful number, since it uses less digits than its factorization.

644125158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35784739 (or 35784736 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 644125158 is about 25379.6209191548. The cubic root of 644125158 is about 863.6214503588.

The spelling of 644125158 in words is "six hundred forty-four million, one hundred twenty-five thousand, one hundred fifty-eight".