639761051 has 4 divisors (see below), whose sum is σ = 677394072. Its totient is φ = 602128032.

The previous prime is 639761047. The next prime is 639761053. The reversal of 639761051 is 150167936.

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

It is not a de Polignac number, because 639761051 - 2² = 639761047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639760996 and 639761014.

It is not an unprimeable number, because it can be changed into a prime (639761053) 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, 18816485 + ... + 18816518.

It is an arithmetic number, because the mean of its divisors is an integer number (169348518).

Almost surely, 2^639761051 is an apocalyptic number.

639761051 is a deficient number, since it is larger than the sum of its proper divisors (37633021).

639761051 is a wasteful number, since it uses less digits than its factorization.

639761051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37633020.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 639761051 is about 25293.4981961768. The cubic root of 639761051 is about 861.6666126594. Note that the first 4 decimals are identical.

The spelling of 639761051 in words is "six hundred thirty-nine million, seven hundred sixty-one thousand, fifty-one".