128721597 has 8 divisors (see below), whose sum is σ = 172148640. Its totient is φ = 85554480.

The previous prime is 128721559. The next prime is 128721601. The reversal of 128721597 is 795127821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128721597 - 2⁶ = 128721533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128721797) 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, 63822 + ... + 65807.

It is an arithmetic number, because the mean of its divisors is an integer number (21518580).

Almost surely, 2^128721597 is an apocalyptic number.

It is an amenable number.

128721597 is a deficient number, since it is larger than the sum of its proper divisors (43427043).

128721597 is a wasteful number, since it uses less digits than its factorization.

128721597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129963.

The product of its digits is 70560, while the sum is 42.

The square root of 128721597 is about 11345.5540631562. The cubic root of 128721597 is about 504.9136825969.

The spelling of 128721597 in words is "one hundred twenty-eight million, seven hundred twenty-one thousand, five hundred ninety-seven".