81786636331 has 4 divisors (see below), whose sum is σ = 84606865200. Its totient is φ = 78966407464.

The previous prime is 81786636329. The next prime is 81786636367. The reversal of 81786636331 is 13363668718.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81786636331 - 2¹ = 81786636329 is a prime.

It is a super-3 number, since 3×81786636331³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81786696331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1410114391 + ... + 1410114448.

It is an arithmetic number, because the mean of its divisors is an integer number (21151716300).

Almost surely, 2^81786636331 is an apocalyptic number.

81786636331 is a deficient number, since it is larger than the sum of its proper divisors (2820228869).

81786636331 is a wasteful number, since it uses less digits than its factorization.

81786636331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2820228868.

The product of its digits is 2612736, while the sum is 52.

The spelling of 81786636331 in words is "eighty-one billion, seven hundred eighty-six million, six hundred thirty-six thousand, three hundred thirty-one".