639664419 has 8 divisors (see below), whose sum is σ = 853273792. Its totient is φ = 426249000.

The previous prime is 639664409. The next prime is 639664427. The reversal of 639664419 is 914466936.

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

It is not a de Polignac number, because 639664419 - 2⁸ = 639664163 is a prime.

It is a super-2 number, since 2×639664419² = 818341137869215122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639664409) 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, 40609 + ... + 54114.

It is an arithmetic number, because the mean of its divisors is an integer number (106659224).

Almost surely, 2^639664419 is an apocalyptic number.

639664419 is a deficient number, since it is larger than the sum of its proper divisors (213609373).

639664419 is a wasteful number, since it uses less digits than its factorization.

639664419 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96977.

The product of its digits is 839808, while the sum is 48.

The square root of 639664419 is about 25291.5879098170. The cubic root of 639664419 is about 861.6232273149.

The spelling of 639664419 in words is "six hundred thirty-nine million, six hundred sixty-four thousand, four hundred nineteen".