81393466851 has 12 divisors (see below), whose sum is σ = 117619554312. Its totient is φ = 54238674336.

The previous prime is 81393466831. The next prime is 81393466907. The reversal of 81393466851 is 15866439318.

81393466851 is a `hidden beast` number, since 8 + 13 + 93 + 466 + 85 + 1 = 666.

It is not a de Polignac number, because 81393466851 - 2⁹ = 81393466339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81393466811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1947921 + ... + 1989266.

It is an arithmetic number, because the mean of its divisors is an integer number (9801629526).

Almost surely, 2^81393466851 is an apocalyptic number.

81393466851 is a deficient number, since it is larger than the sum of its proper divisors (36226087461).

81393466851 is a wasteful number, since it uses less digits than its factorization.

81393466851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3939490 (or 3939487 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 54.

The spelling of 81393466851 in words is "eighty-one billion, three hundred ninety-three million, four hundred sixty-six thousand, eight hundred fifty-one".