128862721 has 8 divisors (see below), whose sum is σ = 144809280. Its totient is φ = 113778192.

The previous prime is 128862707. The next prime is 128862751. The reversal of 128862721 is 127268821.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128862721 is a prime.

It is a super-3 number, since 3×128862721³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128862751) 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, 215191 + ... + 215788.

It is an arithmetic number, because the mean of its divisors is an integer number (18101160).

Almost surely, 2^128862721 is an apocalyptic number.

It is an amenable number.

128862721 is a deficient number, since it is larger than the sum of its proper divisors (15946559).

128862721 is a wasteful number, since it uses less digits than its factorization.

128862721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431015.

The product of its digits is 21504, while the sum is 37.

The square root of 128862721 is about 11351.7717119399. The cubic root of 128862721 is about 505.0981360110.

It can be divided in two parts, 1288 and 62721, that added together give a square (64009 = 253²).

The spelling of 128862721 in words is "one hundred twenty-eight million, eight hundred sixty-two thousand, seven hundred twenty-one".