125685553781 has 2 divisors, whose sum is σ = 125685553782. Its totient is φ = 125685553780.

The previous prime is 125685553769. The next prime is 125685553801. The reversal of 125685553781 is 187355586521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70910364100 + 54775189681 = 266290^2 + 234041^2 .

It is a cyclic number.

It is not a de Polignac number, because 125685553781 - 2¹⁰ = 125685552757 is a prime.

It is a super-2 number, since 2×125685553781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125685553711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62842776890 + 62842776891.

It is an arithmetic number, because the mean of its divisors is an integer number (62842776891).

Almost surely, 2^125685553781 is an apocalyptic number.

It is an amenable number.

125685553781 is a deficient number, since it is larger than the sum of its proper divisors (1).

125685553781 is an equidigital number, since it uses as much as digits as its factorization.

125685553781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080000, while the sum is 56.

The spelling of 125685553781 in words is "one hundred twenty-five billion, six hundred eighty-five million, five hundred fifty-three thousand, seven hundred eighty-one".