639401983 has 4 divisors (see below), whose sum is σ = 697529448. Its totient is φ = 581274520.

The previous prime is 639401969. The next prime is 639401989. The reversal of 639401983 is 389104936.

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

It is a cyclic number.

It is not a de Polignac number, because 639401983 - 2²¹ = 637304831 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639401989) 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, 29063716 + ... + 29063737.

It is an arithmetic number, because the mean of its divisors is an integer number (174382362).

Almost surely, 2^639401983 is an apocalyptic number.

639401983 is a deficient number, since it is larger than the sum of its proper divisors (58127465).

639401983 is a wasteful number, since it uses less digits than its factorization.

639401983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58127464.

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 639401983 is about 25286.3991703050. The cubic root of 639401983 is about 861.5053780817.

The spelling of 639401983 in words is "six hundred thirty-nine million, four hundred one thousand, nine hundred eighty-three".