128749615 has 4 divisors (see below), whose sum is σ = 154499544. Its totient is φ = 102999688.

The previous prime is 128749597. The next prime is 128749627. The reversal of 128749615 is 516947821.

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

It is a cyclic number.

It is not a de Polignac number, because 128749615 - 2⁵ = 128749583 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 12874957 + ... + 12874966.

It is an arithmetic number, because the mean of its divisors is an integer number (38624886).

Almost surely, 2^128749615 is an apocalyptic number.

128749615 is a deficient number, since it is larger than the sum of its proper divisors (25749929).

128749615 is an equidigital number, since it uses as much as digits as its factorization.

128749615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25749928.

The product of its digits is 120960, while the sum is 43.

The square root of 128749615 is about 11346.7887527705. The cubic root of 128749615 is about 504.9503137078.

The spelling of 128749615 in words is "one hundred twenty-eight million, seven hundred forty-nine thousand, six hundred fifteen".