639128954 has 8 divisors (see below), whose sum is σ = 1009151040. Its totient is φ = 302745276.

The previous prime is 639128939. The next prime is 639128977. The reversal of 639128954 is 459821936.

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

It is a super-2 number, since 2×639128954² = 816971639682268232, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 639128899 and 639128908.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8409554 + ... + 8409629.

It is an arithmetic number, because the mean of its divisors is an integer number (126143880).

Almost surely, 2^639128954 is an apocalyptic number.

639128954 is a deficient number, since it is larger than the sum of its proper divisors (370022086).

639128954 is a wasteful number, since it uses less digits than its factorization.

639128954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16819204.

The product of its digits is 466560, while the sum is 47.

The square root of 639128954 is about 25280.9998615561. Note that the first 3 decimals coincide. The cubic root of 639128954 is about 861.3827377366.

The spelling of 639128954 in words is "six hundred thirty-nine million, one hundred twenty-eight thousand, nine hundred fifty-four".