644982075 has 48 divisors (see below), whose sum is σ = 1247241600. Its totient is φ = 325879200.

The previous prime is 644982059. The next prime is 644982119. The reversal of 644982075 is 570289446.

It is a happy number.

It is not a de Polignac number, because 644982075 - 2⁴ = 644982059 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 644982075.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12321 + ... + 37970.

It is an arithmetic number, because the mean of its divisors is an integer number (25984200).

Almost surely, 2^644982075 is an apocalyptic number.

644982075 is a deficient number, since it is larger than the sum of its proper divisors (602259525).

644982075 is a wasteful number, since it uses less digits than its factorization.

644982075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50329 (or 50318 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The square root of 644982075 is about 25396.4972978559. The cubic root of 644982075 is about 864.0042558625.

The spelling of 644982075 in words is "six hundred forty-four million, nine hundred eighty-two thousand, seventy-five".