639370491 has 8 divisors (see below), whose sum is σ = 889559040. Its totient is φ = 407714472.

The previous prime is 639370489. The next prime is 639370517. The reversal of 639370491 is 194073936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 639370491 - 2¹ = 639370489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639300491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4633051 + ... + 4633188.

It is an arithmetic number, because the mean of its divisors is an integer number (111194880).

Almost surely, 2^639370491 is an apocalyptic number.

639370491 is a deficient number, since it is larger than the sum of its proper divisors (250188549).

639370491 is a wasteful number, since it uses less digits than its factorization.

639370491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9266265.

The product of its (nonzero) digits is 122472, while the sum is 42.

The square root of 639370491 is about 25285.7764563400. The cubic root of 639370491 is about 861.4912341506.

The spelling of 639370491 in words is "six hundred thirty-nine million, three hundred seventy thousand, four hundred ninety-one".