639789851 has 8 divisors (see below), whose sum is σ = 662268000. Its totient is φ = 617339520.

The previous prime is 639789847. The next prime is 639789881. The reversal of 639789851 is 158987936.

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

It is a cyclic number.

It is not a de Polignac number, because 639789851 - 2² = 639789847 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639789881) 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, 47075 + ... + 59123.

It is an arithmetic number, because the mean of its divisors is an integer number (82783500).

Almost surely, 2^639789851 is an apocalyptic number.

639789851 is a deficient number, since it is larger than the sum of its proper divisors (22478149).

639789851 is a wasteful number, since it uses less digits than its factorization.

639789851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13909.

The product of its digits is 3265920, while the sum is 56.

The square root of 639789851 is about 25294.0675060379. The cubic root of 639789851 is about 861.6795422920.

The spelling of 639789851 in words is "six hundred thirty-nine million, seven hundred eighty-nine thousand, eight hundred fifty-one".