128978926 has 4 divisors (see below), whose sum is σ = 193468392. Its totient is φ = 64489462.

The previous prime is 128978911. The next prime is 128978933. The reversal of 128978926 is 629879821.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×128978926² = 33271126704226952, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32244730 + ... + 32244733.

It is an arithmetic number, because the mean of its divisors is an integer number (48367098).

Almost surely, 2^128978926 is an apocalyptic number.

128978926 is a deficient number, since it is larger than the sum of its proper divisors (64489466).

128978926 is an equidigital number, since it uses as much as digits as its factorization.

128978926 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64489465.

The product of its digits is 870912, while the sum is 52.

The square root of 128978926 is about 11356.8889225879. Note that the first 3 decimals coincide. The cubic root of 128978926 is about 505.2499184507.

The spelling of 128978926 in words is "one hundred twenty-eight million, nine hundred seventy-eight thousand, nine hundred twenty-six".