81091465806401 has 8 divisors (see below), whose sum is σ = 81235786043880. Its totient is φ = 80947151901568.

The previous prime is 81091465806367. The next prime is 81091465806413. The reversal of 81091465806401 is 10460856419018.

It is a Cunningham number, because it is equal to 9005080²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 784507004176 + 80306958802225 = 885724^2 + 8961415^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81091465806401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81091465896401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24430175 + ... + 27550251.

It is an arithmetic number, because the mean of its divisors is an integer number (10154473255485).

Almost surely, 2^{81091465806401} is an apocalyptic number.

It is an amenable number.

81091465806401 is a deficient number, since it is larger than the sum of its proper divisors (144320237479).

81091465806401 is a wasteful number, since it uses less digits than its factorization.

81091465806401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3166323.

The product of its (nonzero) digits is 1658880, while the sum is 53.

The spelling of 81091465806401 in words is "eighty-one trillion, ninety-one billion, four hundred sixty-five million, eight hundred six thousand, four hundred one".