647138688 has 192 divisors, whose sum is σ = 2021411520. Its totient is φ = 182891520.

The previous prime is 647138623. The next prime is 647138693. The reversal of 647138688 is 886831746.

It is a tau number, because it is divible by the number of its divisors (192).

It is a super-2 number, since 2×647138688² = 837576963012722688, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 647138688.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3066903 + ... + 3067113.

It is an arithmetic number, because the mean of its divisors is an integer number (10528185).

Almost surely, 2^647138688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 647138688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1010705760).

647138688 is an abundant number, since it is smaller than the sum of its proper divisors (1374272832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

647138688 is a wasteful number, since it uses less digits than its factorization.

647138688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405 (or 386 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 51.

The square root of 647138688 is about 25438.9207318235. The cubic root of 647138688 is about 864.9661688351.

The spelling of 647138688 in words is "six hundred forty-seven million, one hundred thirty-eight thousand, six hundred eighty-eight".