125721 has 12 divisors (see below), whose sum is σ = 185380. Its totient is φ = 82080.

The previous prime is 125717. The next prime is 125731. The reversal of 125721 is 127521.

It can be written as a sum of positive squares in 2 ways, for example, as 57600 + 68121 = 240^2 + 261^2 .

It is not a de Polignac number, because 125721 - 2² = 125717 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 125694 and 125703.

It is not an unprimeable number, because it can be changed into a prime (125711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 435 + ... + 663.

2¹²⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

125721 is a deficient number, since it is larger than the sum of its proper divisors (59659).

125721 is a wasteful number, since it uses less digits than its factorization.

125721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296 (or 293 counting only the distinct ones).

The product of its digits is 140, while the sum is 18.

The square root of 125721 is about 354.5715724646. The cubic root of 125721 is about 50.0959490910.

The spelling of 125721 in words is "one hundred twenty-five thousand, seven hundred twenty-one".