125661621 has 4 divisors (see below), whose sum is σ = 167548832. Its totient is φ = 83774412.

The previous prime is 125661607. The next prime is 125661623. The reversal of 125661621 is 126166521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 125661621 - 2⁷ = 125661493 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 (125661623) 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, 20943601 + ... + 20943606.

It is an arithmetic number, because the mean of its divisors is an integer number (41887208).

Almost surely, 2^125661621 is an apocalyptic number.

It is an amenable number.

125661621 is a deficient number, since it is larger than the sum of its proper divisors (41887211).

125661621 is an equidigital number, since it uses as much as digits as its factorization.

125661621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41887210.

The product of its digits is 4320, while the sum is 30.

The square root of 125661621 is about 11209.8894285359. The cubic root of 125661621 is about 500.8806094767.

The spelling of 125661621 in words is "one hundred twenty-five million, six hundred sixty-one thousand, six hundred twenty-one".