125991961 has 2 divisors, whose sum is σ = 125991962. Its totient is φ = 125991960.

The previous prime is 125991923. The next prime is 125991973. The reversal of 125991961 is 169199521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100801600 + 25190361 = 10040^2 + 5019^2 .

It is a cyclic number.

It is not a de Polignac number, because 125991961 - 2²¹ = 123894809 is a prime.

It is not a weakly prime, because it can be changed into another prime (125991461) 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 as a sum of consecutive naturals, namely, 62995980 + 62995981.

It is an arithmetic number, because the mean of its divisors is an integer number (62995981).

Almost surely, 2^125991961 is an apocalyptic number.

It is an amenable number.

125991961 is a deficient number, since it is larger than the sum of its proper divisors (1).

125991961 is an equidigital number, since it uses as much as digits as its factorization.

125991961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43740, while the sum is 43.

The square root of 125991961 is about 11224.6140690894. The cubic root of 125991961 is about 501.3191313908.

The spelling of 125991961 in words is "one hundred twenty-five million, nine hundred ninety-one thousand, nine hundred sixty-one".