128725931 has 8 divisors (see below), whose sum is σ = 135635280. Its totient is φ = 121830048.

The previous prime is 128725913. The next prime is 128725939. The reversal of 128725931 is 139527821.

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 128725931 - 2¹⁸ = 128463787 is a prime.

It is a super-2 number, since 2×128725931² = 33140730623633522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128725939) 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, 20765 + ... + 26241.

It is an arithmetic number, because the mean of its divisors is an integer number (16954410).

Almost surely, 2^128725931 is an apocalyptic number.

128725931 is a deficient number, since it is larger than the sum of its proper divisors (6909349).

128725931 is a wasteful number, since it uses less digits than its factorization.

128725931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6733.

The product of its digits is 30240, while the sum is 38.

The square root of 128725931 is about 11345.7450614757. The cubic root of 128725931 is about 504.9193492744.

The spelling of 128725931 in words is "one hundred twenty-eight million, seven hundred twenty-five thousand, nine hundred thirty-one".