128992706 has 4 divisors (see below), whose sum is σ = 193489062. Its totient is φ = 64496352.

The previous prime is 128992681. The next prime is 128992709. The reversal of 128992706 is 607299821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 607299821 = 233 ⋅2606437.

It can be written as a sum of positive squares in only one way, i.e., 105904681 + 23088025 = 10291^2 + 4805^2 .

It is not an unprimeable number, because it can be changed into a prime (128992709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32248175 + ... + 32248178.

Almost surely, 2^128992706 is an apocalyptic number.

128992706 is a deficient number, since it is larger than the sum of its proper divisors (64496356).

128992706 is an equidigital number, since it uses as much as digits as its factorization.

128992706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64496355.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 128992706 is about 11357.4955866159. The cubic root of 128992706 is about 505.2679113021.

The spelling of 128992706 in words is "one hundred twenty-eight million, nine hundred ninety-two thousand, seven hundred six".