81811494 has 24 divisors (see below), whose sum is σ = 183371760. Its totient is φ = 26329968.

The previous prime is 81811447. The next prime is 81811517. The reversal of 81811494 is 49411818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77842 + ... + 78885.

It is an arithmetic number, because the mean of its divisors is an integer number (7640490).

Almost surely, 2^81811494 is an apocalyptic number.

81811494 is an abundant number, since it is smaller than the sum of its proper divisors (101560266).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81811494 is a wasteful number, since it uses less digits than its factorization.

81811494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156764 (or 156761 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 81811494 is about 9044.9706467185. The cubic root of 81811494 is about 434.1149822408.

The spelling of 81811494 in words is "eighty-one million, eight hundred eleven thousand, four hundred ninety-four".