647981756 has 12 divisors (see below), whose sum is σ = 1134276360. Its totient is φ = 323902800.

The previous prime is 647981731. The next prime is 647981759. The reversal of 647981756 is 657189746.

It is a super-2 number, since 2×647981756² = 839760712217687072, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 647981698 and 647981707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647981759) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3791 + ... + 36198.

It is an arithmetic number, because the mean of its divisors is an integer number (94523030).

Almost surely, 2^647981756 is an apocalyptic number.

It is an amenable number.

647981756 is a deficient number, since it is larger than the sum of its proper divisors (486294604).

647981756 is a wasteful number, since it uses less digits than its factorization.

647981756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44044 (or 44042 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 53.

The square root of 647981756 is about 25455.4857741902. The cubic root of 647981756 is about 865.3416209968.

The spelling of 647981756 in words is "six hundred forty-seven million, nine hundred eighty-one thousand, seven hundred fifty-six".