639864129 has 8 divisors (see below), whose sum is σ = 859665312. Its totient is φ = 423319520.

The previous prime is 639864109. The next prime is 639864179. The reversal of 639864129 is 921468936.

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 639864129 - 2⁵ = 639864097 is a prime.

It is a super-2 number, since 2×639864129² = 818852207161857282, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (639864109) 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, 813684 + ... + 814469.

It is an arithmetic number, because the mean of its divisors is an integer number (107458164).

Almost surely, 2^639864129 is an apocalyptic number.

It is an amenable number.

639864129 is a deficient number, since it is larger than the sum of its proper divisors (219801183).

639864129 is a wasteful number, since it uses less digits than its factorization.

639864129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1628287.

The product of its digits is 559872, while the sum is 48.

The square root of 639864129 is about 25295.5357523813. The cubic root of 639864129 is about 861.7128872808.

The spelling of 639864129 in words is "six hundred thirty-nine million, eight hundred sixty-four thousand, one hundred twenty-nine".