128971997 has 32 divisors (see below), whose sum is σ = 168542208. Its totient is φ = 95760000.

The previous prime is 128971993. The next prime is 128972021. The reversal of 128971997 is 799179821.

It is not a de Polignac number, because 128971997 - 2² = 128971993 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128971993) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 169097 + ... + 169857.

It is an arithmetic number, because the mean of its divisors is an integer number (5266944).

Almost surely, 2^128971997 is an apocalyptic number.

It is an amenable number.

128971997 is a deficient number, since it is larger than the sum of its proper divisors (39570211).

128971997 is a wasteful number, since it uses less digits than its factorization.

128971997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 881.

The product of its digits is 571536, while the sum is 53.

The square root of 128971997 is about 11356.5838613555. The cubic root of 128971997 is about 505.2408706176.

The spelling of 128971997 in words is "one hundred twenty-eight million, nine hundred seventy-one thousand, nine hundred ninety-seven".