125661875781 has 16 divisors (see below), whose sum is σ = 185314258304. Its totient is φ = 75240373824.

The previous prime is 125661875777. The next prime is 125661875789. The reversal of 125661875781 is 187578166521.

It is not a de Polignac number, because 125661875781 - 2² = 125661875777 is a prime.

It is a super-2 number, since 2×125661875781² (a number of 23 digits) 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 (125661875789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43540441 + ... + 43543326.

It is an arithmetic number, because the mean of its divisors is an integer number (11582141144).

Almost surely, 2^125661875781 is an apocalyptic number.

It is an amenable number.

125661875781 is a deficient number, since it is larger than the sum of its proper divisors (59652382523).

125661875781 is a wasteful number, since it uses less digits than its factorization.

125661875781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87083820.

The product of its digits is 5644800, while the sum is 57.

The spelling of 125661875781 in words is "one hundred twenty-five billion, six hundred sixty-one million, eight hundred seventy-five thousand, seven hundred eighty-one".