639769757 has 4 divisors (see below), whose sum is σ = 697930656. Its totient is φ = 581608860.

The previous prime is 639769747. The next prime is 639769759. The reversal of 639769757 is 757967936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639769757 - 2¹² = 639765661 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639769696 and 639769705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639769759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29080433 + ... + 29080454.

It is an arithmetic number, because the mean of its divisors is an integer number (174482664).

Almost surely, 2^639769757 is an apocalyptic number.

It is an amenable number.

639769757 is a deficient number, since it is larger than the sum of its proper divisors (58160899).

639769757 is a wasteful number, since it uses less digits than its factorization.

639769757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58160898.

The product of its digits is 15002820, while the sum is 59.

The square root of 639769757 is about 25293.6702951549. The cubic root of 639769757 is about 861.6705212205.

The spelling of 639769757 in words is "six hundred thirty-nine million, seven hundred sixty-nine thousand, seven hundred fifty-seven".