81005694133 has 16 divisors (see below), whose sum is σ = 100059272320. Its totient is φ = 63861016896.

The previous prime is 81005694131. The next prime is 81005694157. The reversal of 81005694133 is 33149650018.

It is a cyclic number.

It is not a de Polignac number, because 81005694133 - 2¹ = 81005694131 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81005694131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1581603 + ... + 1632016.

It is an arithmetic number, because the mean of its divisors is an integer number (6253704520).

Almost surely, 2^81005694133 is an apocalyptic number.

It is an amenable number.

81005694133 is a deficient number, since it is larger than the sum of its proper divisors (19053578187).

81005694133 is a wasteful number, since it uses less digits than its factorization.

81005694133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3213916.

The product of its (nonzero) digits is 77760, while the sum is 40.

The spelling of 81005694133 in words is "eighty-one billion, five million, six hundred ninety-four thousand, one hundred thirty-three".