81394118461 has 8 divisors (see below), whose sum is σ = 82800014904. Its totient is φ = 79999987200.

The previous prime is 81394118419. The next prime is 81394118479. The reversal of 81394118461 is 16481149318.

It can be written as a sum of positive squares in 4 ways, for example, as 48149524900 + 33244593561 = 219430^2 + 182331^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81394118461 - 2²¹ = 81392021309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81394118401) 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, 2927340 + ... + 2955013.

It is an arithmetic number, because the mean of its divisors is an integer number (10350001863).

Almost surely, 2^81394118461 is an apocalyptic number.

It is an amenable number.

81394118461 is a deficient number, since it is larger than the sum of its proper divisors (1405896443).

81394118461 is a wasteful number, since it uses less digits than its factorization.

81394118461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5882591.

The product of its digits is 165888, while the sum is 46.

The spelling of 81394118461 in words is "eighty-one billion, three hundred ninety-four million, one hundred eighteen thousand, four hundred sixty-one".