639640275 has 24 divisors (see below), whose sum is σ = 1086125424. Its totient is φ = 331920000.

The previous prime is 639640271. The next prime is 639640297. The reversal of 639640275 is 572046936.

It is not a de Polignac number, because 639640275 - 2² = 639640271 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639640271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 112476 + ... + 118025.

It is an arithmetic number, because the mean of its divisors is an integer number (45255226).

Almost surely, 2^639640275 is an apocalyptic number.

639640275 is a deficient number, since it is larger than the sum of its proper divisors (446485149).

639640275 is a wasteful number, since it uses less digits than its factorization.

639640275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230551 (or 230546 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 42.

The square root of 639640275 is about 25291.1105924592. The cubic root of 639640275 is about 861.6123865822.

The spelling of 639640275 in words is "six hundred thirty-nine million, six hundred forty thousand, two hundred seventy-five".