1231424455561 has 2 divisors, whose sum is σ = 1231424455562. Its totient is φ = 1231424455560.

The previous prime is 1231424455507. The next prime is 1231424455589. The reversal of 1231424455561 is 1655544241321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1000790156025 + 230634299536 = 1000395^2 + 480244^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231424455561 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231424459561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615712227780 + 615712227781.

It is an arithmetic number, because the mean of its divisors is an integer number (615712227781).

Almost surely, 2^{1231424455561} is an apocalyptic number.

It is an amenable number.

1231424455561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231424455561 is an equidigital number, since it uses as much as digits as its factorization.

1231424455561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576000, while the sum is 43.

Adding to 1231424455561 its reverse (1655544241321), we get a palindrome (2886968696882).

The spelling of 1231424455561 in words is "one trillion, two hundred thirty-one billion, four hundred twenty-four million, four hundred fifty-five thousand, five hundred sixty-one".