128256631 has 8 divisors (see below), whose sum is σ = 135129600. Its totient is φ = 121395960.

The previous prime is 128256629. The next prime is 128256643. The reversal of 128256631 is 136652821.

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

It is a cyclic number.

It is not a de Polignac number, because 128256631 - 2¹ = 128256629 is a prime.

It is a super-2 number, since 2×128256631² = 32899526790940322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128254631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24996 + ... + 29686.

It is an arithmetic number, because the mean of its divisors is an integer number (16891200).

Almost surely, 2^128256631 is an apocalyptic number.

128256631 is a deficient number, since it is larger than the sum of its proper divisors (6872969).

128256631 is a wasteful number, since it uses less digits than its factorization.

128256631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6149.

The product of its digits is 17280, while the sum is 34.

The square root of 128256631 is about 11325.0444149239. The cubic root of 128256631 is about 504.3050021991.

The spelling of 128256631 in words is "one hundred twenty-eight million, two hundred fifty-six thousand, six hundred thirty-one".