128120761 has 4 divisors (see below), whose sum is σ = 128157300. Its totient is φ = 128084224.

The previous prime is 128120749. The next prime is 128120807. The reversal of 128120761 is 167021821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 49266361 + 78854400 = 7019^2 + 8880^2 .

It is a cyclic number.

It is not a de Polignac number, because 128120761 - 2⁷ = 128120633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128120711) 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, 12376 + ... + 20233.

It is an arithmetic number, because the mean of its divisors is an integer number (32039325).

Almost surely, 2^128120761 is an apocalyptic number.

It is an amenable number.

128120761 is a deficient number, since it is larger than the sum of its proper divisors (36539).

128120761 is an equidigital number, since it uses as much as digits as its factorization.

128120761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36538.

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 128120761 is about 11319.0441734274. The cubic root of 128120761 is about 504.1268590233.

It can be divided in two parts, 128120 and 761, that added together give a square (128881 = 359²).

The spelling of 128120761 in words is "one hundred twenty-eight million, one hundred twenty thousand, seven hundred sixty-one".