128779507 has 4 divisors (see below), whose sum is σ = 134378640. Its totient is φ = 123180376.

The previous prime is 128779493. The next prime is 128779513. The reversal of 128779507 is 705977821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 705977821 = 983 ⋅718187.

It is a cyclic number.

It is not a de Polignac number, because 128779507 - 2⁷ = 128779379 is a prime.

It is a super-2 number, since 2×128779507² = 33168322846326098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128779307) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2799532 + ... + 2799577.

It is an arithmetic number, because the mean of its divisors is an integer number (33594660).

Almost surely, 2^128779507 is an apocalyptic number.

128779507 is a deficient number, since it is larger than the sum of its proper divisors (5599133).

128779507 is an equidigital number, since it uses as much as digits as its factorization.

128779507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5599132.

The product of its (nonzero) digits is 246960, while the sum is 46.

The square root of 128779507 is about 11348.1058771938. The cubic root of 128779507 is about 504.9893890526.

It can be divided in two parts, 128779 and 507, that added together give a triangular number (129286 = T₅₀₈).

The spelling of 128779507 in words is "one hundred twenty-eight million, seven hundred seventy-nine thousand, five hundred seven".