128392731 has 12 divisors (see below), whose sum is σ = 191439040. Its totient is φ = 82833840.

The previous prime is 128392729. The next prime is 128392751. The reversal of 128392731 is 137293821.

It is not a de Polignac number, because 128392731 - 2¹ = 128392729 is a prime.

It is a super-2 number, since 2×128392731² = 32969386747276722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128392751) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 229816 + ... + 230373.

Almost surely, 2^128392731 is an apocalyptic number.

128392731 is a deficient number, since it is larger than the sum of its proper divisors (63046309).

128392731 is a wasteful number, since it uses less digits than its factorization.

128392731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460226 (or 460223 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 128392731 is about 11331.0516281588. The cubic root of 128392731 is about 504.4833208477.

The spelling of 128392731 in words is "one hundred twenty-eight million, three hundred ninety-two thousand, seven hundred thirty-one".