81126567461 has 2 divisors, whose sum is σ = 81126567462. Its totient is φ = 81126567460.

The previous prime is 81126567427. The next prime is 81126567463. The reversal of 81126567461 is 16476562118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63498960100 + 17627607361 = 251990^2 + 132769^2 .

It is a cyclic number.

It is not a de Polignac number, because 81126567461 - 2⁶ = 81126567397 is a prime.

Together with 81126567463, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81126567463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40563283730 + 40563283731.

It is an arithmetic number, because the mean of its divisors is an integer number (40563283731).

Almost surely, 2^81126567461 is an apocalyptic number.

It is an amenable number.

81126567461 is a deficient number, since it is larger than the sum of its proper divisors (1).

81126567461 is an equidigital number, since it uses as much as digits as its factorization.

81126567461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 483840, while the sum is 47.

The spelling of 81126567461 in words is "eighty-one billion, one hundred twenty-six million, five hundred sixty-seven thousand, four hundred sixty-one".