123611578261 has 2 divisors, whose sum is σ = 123611578262. Its totient is φ = 123611578260.

The previous prime is 123611578247. The next prime is 123611578267. The reversal of 123611578261 is 162875116321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120565200625 + 3046377636 = 347225^2 + 55194^2 .

It is a cyclic number.

It is not a de Polignac number, because 123611578261 - 2⁷ = 123611578133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123611578267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61805789130 + 61805789131.

It is an arithmetic number, because the mean of its divisors is an integer number (61805789131).

Almost surely, 2^123611578261 is an apocalyptic number.

It is an amenable number.

123611578261 is a deficient number, since it is larger than the sum of its proper divisors (1).

123611578261 is an equidigital number, since it uses as much as digits as its factorization.

123611578261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 43.

The spelling of 123611578261 in words is "one hundred twenty-three billion, six hundred eleven million, five hundred seventy-eight thousand, two hundred sixty-one".