647128131 has 32 divisors (see below), whose sum is σ = 966432768. Its totient is φ = 382475520.

The previous prime is 647128121. The next prime is 647128213. The reversal of 647128131 is 131821746.

It is not a de Polignac number, because 647128131 - 2⁵ = 647128099 is a prime.

It is a super-2 number, since 2×647128131² = 837549635863106322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 647128092 and 647128101.

It is not an unprimeable number, because it can be changed into a prime (647128121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 163680 + ... + 167586.

It is an arithmetic number, because the mean of its divisors is an integer number (30201024).

Almost surely, 2^647128131 is an apocalyptic number.

647128131 is a deficient number, since it is larger than the sum of its proper divisors (319304637).

647128131 is a wasteful number, since it uses less digits than its factorization.

647128131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4091.

The product of its digits is 8064, while the sum is 33.

The square root of 647128131 is about 25438.7132339668. The cubic root of 647128131 is about 864.9614653109.

Adding to 647128131 its reverse (131821746), we get a palindrome (778949877).

It can be divided in two parts, 647 and 128131, that added together give a triangular number (128778 = T₅₀₇).

The spelling of 647128131 in words is "six hundred forty-seven million, one hundred twenty-eight thousand, one hundred thirty-one".