125721613 has 8 divisors (see below), whose sum is σ = 140123520. Its totient is φ = 112098240.

The previous prime is 125721599. The next prime is 125721619. The reversal of 125721613 is 316127521.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 125721613 - 2¹⁷ = 125590541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125721619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194293 + ... + 194938.

It is an arithmetic number, because the mean of its divisors is an integer number (17515440).

Almost surely, 2^125721613 is an apocalyptic number.

It is an amenable number.

125721613 is a deficient number, since it is larger than the sum of its proper divisors (14401907).

125721613 is a wasteful number, since it uses less digits than its factorization.

125721613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389267.

The product of its digits is 2520, while the sum is 28.

The square root of 125721613 is about 11212.5649607929. The cubic root of 125721613 is about 500.9603051141.

The spelling of 125721613 in words is "one hundred twenty-five million, seven hundred twenty-one thousand, six hundred thirteen".