128705992 has 16 divisors (see below), whose sum is σ = 241649100. Its totient is φ = 64266240.

The previous prime is 128705989. The next prime is 128706013. The reversal of 128705992 is 299507821.

It can be written as a sum of positive squares in 2 ways, for example, as 128278276 + 427716 = 11326^2 + 654^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4309 + ... + 16612.

Almost surely, 2^128705992 is an apocalyptic number.

It is an amenable number.

128705992 is a deficient number, since it is larger than the sum of its proper divisors (112943108).

128705992 is a wasteful number, since it uses less digits than its factorization.

128705992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21696 (or 21692 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 128705992 is about 11344.8663279917. The cubic root of 128705992 is about 504.8932781048.

The spelling of 128705992 in words is "one hundred twenty-eight million, seven hundred five thousand, nine hundred ninety-two".