125256991 has 4 divisors (see below), whose sum is σ = 125310232. Its totient is φ = 125203752.

The previous prime is 125256959. The next prime is 125257001. The reversal of 125256991 is 199652521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199652521 = 199 ⋅1003279.

It is a cyclic number.

It is not a de Polignac number, because 125256991 - 2⁵ = 125256959 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 (125256491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22920 + ... + 27853.

It is an arithmetic number, because the mean of its divisors is an integer number (31327558).

Almost surely, 2^125256991 is an apocalyptic number.

125256991 is a deficient number, since it is larger than the sum of its proper divisors (53241).

125256991 is an equidigital number, since it uses as much as digits as its factorization.

125256991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53240.

The product of its digits is 48600, while the sum is 40.

The square root of 125256991 is about 11191.8269732872. The cubic root of 125256991 is about 500.3424201101.

The spelling of 125256991 in words is "one hundred twenty-five million, two hundred fifty-six thousand, nine hundred ninety-one".