128031993 has 12 divisors (see below), whose sum is σ = 185146260. Its totient is φ = 85257216.

The previous prime is 128031989. The next prime is 128032019. The reversal of 128031993 is 399130821.

It can be written as a sum of positive squares in 2 ways, for example, as 725904 + 127306089 = 852^2 + 11283^2 .

It is not a de Polignac number, because 128031993 - 2² = 128031989 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (128031983) 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, 705 + ... + 16017.

It is an arithmetic number, because the mean of its divisors is an integer number (15428855).

Almost surely, 2^128031993 is an apocalyptic number.

It is an amenable number.

128031993 is a deficient number, since it is larger than the sum of its proper divisors (57114267).

128031993 is a wasteful number, since it uses less digits than its factorization.

128031993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16248 (or 16245 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 128031993 is about 11315.1223148493. The cubic root of 128031993 is about 504.0104046416.

The spelling of 128031993 in words is "one hundred twenty-eight million, thirty-one thousand, nine hundred ninety-three".