128257992 has 80 divisors (see below), whose sum is σ = 367675440. Its totient is φ = 41749344.

The previous prime is 128257973. The next prime is 128258003. The reversal of 128257992 is 299752821.

It is a happy number.

It is a super-2 number, since 2×128257992² = 32900225023744128, which contains 22 as substring.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25563 + ... + 30165.

It is an arithmetic number, because the mean of its divisors is an integer number (4595943).

Almost surely, 2^128257992 is an apocalyptic number.

128257992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128257992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183837720).

128257992 is an abundant number, since it is smaller than the sum of its proper divisors (239417448).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128257992 is a wasteful number, since it uses less digits than its factorization.

128257992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4664 (or 4651 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 128257992 is about 11325.1045028291. The cubic root of 128257992 is about 504.3067860098.

The spelling of 128257992 in words is "one hundred twenty-eight million, two hundred fifty-seven thousand, nine hundred ninety-two".