125957021 has 4 divisors (see below), whose sum is σ = 127112700. Its totient is φ = 124801344.

The previous prime is 125956997. The next prime is 125957059. The reversal of 125957021 is 120759521.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120759521 = 193 ⋅625697.

It can be written as a sum of positive squares in 2 ways, for example, as 103022500 + 22934521 = 10150^2 + 4789^2 .

It is a cyclic number.

It is not a de Polignac number, because 125957021 - 2²² = 121762717 is a prime.

It is a super-2 number, since 2×125957021² = 31730342278388882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125957921) 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, 577676 + ... + 577893.

It is an arithmetic number, because the mean of its divisors is an integer number (31778175).

Almost surely, 2^125957021 is an apocalyptic number.

It is an amenable number.

125957021 is a deficient number, since it is larger than the sum of its proper divisors (1155679).

125957021 is a wasteful number, since it uses less digits than its factorization.

125957021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1155678.

The product of its (nonzero) digits is 6300, while the sum is 32.

The square root of 125957021 is about 11223.0575602195. The cubic root of 125957021 is about 501.2727852860.

The spelling of 125957021 in words is "one hundred twenty-five million, nine hundred fifty-seven thousand, twenty-one".