81436910761 has 2 divisors, whose sum is σ = 81436910762. Its totient is φ = 81436910760.

The previous prime is 81436910749. The next prime is 81436910791. The reversal of 81436910761 is 16701963418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79873499161 + 1563411600 = 282619^2 + 39540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81436910761 is a prime.

It is a super-5 number, since 5×81436910761⁵ (a number of 56 digits) contains 55555 as substring.

It is not a weakly prime, because it can be changed into another prime (81436910701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40718455380 + 40718455381.

It is an arithmetic number, because the mean of its divisors is an integer number (40718455381).

Almost surely, 2^81436910761 is an apocalyptic number.

It is an amenable number.

81436910761 is a deficient number, since it is larger than the sum of its proper divisors (1).

81436910761 is an equidigital number, since it uses as much as digits as its factorization.

81436910761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 46.

The spelling of 81436910761 in words is "eighty-one billion, four hundred thirty-six million, nine hundred ten thousand, seven hundred sixty-one".