125643631 has 4 divisors (see below), whose sum is σ = 129976200. Its totient is φ = 121311064.

The previous prime is 125643613. The next prime is 125643647. The reversal of 125643631 is 136346521.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125643631 is a prime.

It is a super-2 number, since 2×125643631² = 31572644021728322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 125643593 and 125643602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125643671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2166241 + ... + 2166298.

It is an arithmetic number, because the mean of its divisors is an integer number (32494050).

Almost surely, 2^125643631 is an apocalyptic number.

125643631 is a deficient number, since it is larger than the sum of its proper divisors (4332569).

125643631 is an equidigital number, since it uses as much as digits as its factorization.

125643631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4332568.

The product of its digits is 12960, while the sum is 31.

The square root of 125643631 is about 11209.0869833363. The cubic root of 125643631 is about 500.8567059382.

The spelling of 125643631 in words is "one hundred twenty-five million, six hundred forty-three thousand, six hundred thirty-one".