81209695994 has 16 divisors (see below), whose sum is σ = 146543812800. Its totient is φ = 32972357664.

The previous prime is 81209695993. The next prime is 81209696077. The reversal of 81209695994 is 49959690218.

It is a Smith number, since the sum of its digits (62) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81209695991) 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, 152649539 + ... + 152650070.

It is an arithmetic number, because the mean of its divisors is an integer number (9158988300).

Almost surely, 2^81209695994 is an apocalyptic number.

81209695994 is a deficient number, since it is larger than the sum of its proper divisors (65334116806).

81209695994 is a wasteful number, since it uses less digits than its factorization.

81209695994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305299637.

The product of its (nonzero) digits is 12597120, while the sum is 62.

The spelling of 81209695994 in words is "eighty-one billion, two hundred nine million, six hundred ninety-five thousand, nine hundred ninety-four".