639429463521 has 16 divisors (see below), whose sum is σ = 947570574720. Its totient is φ = 426165859440.

The previous prime is 639429463513. The next prime is 639429463523. The reversal of 639429463521 is 125364924936.

639429463521 is a `hidden beast` number, since 6 + 3 + 94 + 29 + 4 + 6 + 3 + 521 = 666.

It is not a de Polignac number, because 639429463521 - 2³ = 639429463513 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (639429463523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3248445 + ... + 3439658.

It is an arithmetic number, because the mean of its divisors is an integer number (59223160920).

Almost surely, 2^639429463521 is an apocalyptic number.

It is an amenable number.

639429463521 is a deficient number, since it is larger than the sum of its proper divisors (308141111199).

639429463521 is a wasteful number, since it uses less digits than its factorization.

639429463521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6691653 (or 6691647 counting only the distinct ones).

The product of its digits is 8398080, while the sum is 54.

The spelling of 639429463521 in words is "six hundred thirty-nine billion, four hundred twenty-nine million, four hundred sixty-three thousand, five hundred twenty-one".