128125861 has 4 divisors (see below), whose sum is σ = 131250924. Its totient is φ = 125000800.

The previous prime is 128125859. The next prime is 128125919. The reversal of 128125861 is 168521821.

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 2461761 + 125664100 = 1569^2 + 11210^2 .

It is not a de Polignac number, because 128125861 - 2¹ = 128125859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128125061) 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, 1562470 + ... + 1562551.

It is an arithmetic number, because the mean of its divisors is an integer number (32812731).

Almost surely, 2^128125861 is an apocalyptic number.

It is an amenable number.

128125861 is a deficient number, since it is larger than the sum of its proper divisors (3125063).

128125861 is an equidigital number, since it uses as much as digits as its factorization.

128125861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3125062.

The product of its digits is 7680, while the sum is 34.

The square root of 128125861 is about 11319.2694552255. The cubic root of 128125861 is about 504.1335480586.

The spelling of 128125861 in words is "one hundred twenty-eight million, one hundred twenty-five thousand, eight hundred sixty-one".