125557871561 has 4 divisors (see below), whose sum is σ = 127431869712. Its totient is φ = 123683873412.

The previous prime is 125557871477. The next prime is 125557871573. The reversal of 125557871561 is 165178755521.

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, and also an emirpimes, since its reverse is a distinct semiprime: 165178755521 = 13 ⋅12706058117.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125557871561 is a prime.

It is a super-2 number, since 2×125557871561² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125557877561) 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, 936998975 + ... + 936999108.

It is an arithmetic number, because the mean of its divisors is an integer number (31857967428).

Almost surely, 2^125557871561 is an apocalyptic number.

It is an amenable number.

125557871561 is a deficient number, since it is larger than the sum of its proper divisors (1873998151).

125557871561 is an equidigital number, since it uses as much as digits as its factorization.

125557871561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1873998150.

The product of its digits is 2940000, while the sum is 53.

The spelling of 125557871561 in words is "one hundred twenty-five billion, five hundred fifty-seven million, eight hundred seventy-one thousand, five hundred sixty-one".