128386931 has 2 divisors, whose sum is σ = 128386932. Its totient is φ = 128386930.

The previous prime is 128386927. The next prime is 128386981. The reversal of 128386931 is 139683821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128386931 - 2² = 128386927 is a prime.

It is a super-2 number, since 2×128386931² = 32966408103197522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (128386901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64193465 + 64193466.

It is an arithmetic number, because the mean of its divisors is an integer number (64193466).

Almost surely, 2^128386931 is an apocalyptic number.

128386931 is a deficient number, since it is larger than the sum of its proper divisors (1).

128386931 is an equidigital number, since it uses as much as digits as its factorization.

128386931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 41.

The square root of 128386931 is about 11330.7956913890. The cubic root of 128386931 is about 504.4757242408.

The spelling of 128386931 in words is "one hundred twenty-eight million, three hundred eighty-six thousand, nine hundred thirty-one".