123991828781 has 2 divisors, whose sum is σ = 123991828782. Its totient is φ = 123991828780.

The previous prime is 123991828739. The next prime is 123991828811. The reversal of 123991828781 is 187828199321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120888336100 + 3103492681 = 347690^2 + 55709^2 .

It is a cyclic number.

It is not a de Polignac number, because 123991828781 - 2³⁰ = 122918086957 is a prime.

It is a super-2 number, since 2×123991828781² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 123991828781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123991821781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61995914390 + 61995914391.

It is an arithmetic number, because the mean of its divisors is an integer number (61995914391).

Almost surely, 2^123991828781 is an apocalyptic number.

It is an amenable number.

123991828781 is a deficient number, since it is larger than the sum of its proper divisors (1).

123991828781 is an equidigital number, since it uses as much as digits as its factorization.

123991828781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3483648, while the sum is 59.

The spelling of 123991828781 in words is "one hundred twenty-three billion, nine hundred ninety-one million, eight hundred twenty-eight thousand, seven hundred eighty-one".