639676285 has 4 divisors (see below), whose sum is σ = 767611548. Its totient is φ = 511741024.

The previous prime is 639676283. The next prime is 639676291. The reversal of 639676285 is 582676936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 184579396 + 455096889 = 13586^2 + 21333^2 .

It is a cyclic number.

It is not a de Polignac number, because 639676285 - 2¹ = 639676283 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639676283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63967624 + ... + 63967633.

It is an arithmetic number, because the mean of its divisors is an integer number (191902887).

Almost surely, 2^639676285 is an apocalyptic number.

It is an amenable number.

639676285 is a deficient number, since it is larger than the sum of its proper divisors (127935263).

639676285 is a wasteful number, since it uses less digits than its factorization.

639676285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127935262.

The product of its digits is 3265920, while the sum is 52.

The square root of 639676285 is about 25291.8224926556. The cubic root of 639676285 is about 861.6285550866.

The spelling of 639676285 in words is "six hundred thirty-nine million, six hundred seventy-six thousand, two hundred eighty-five".