81445194 has 12 divisors (see below), whose sum is σ = 176464626. Its totient is φ = 27148392.

The previous prime is 81445183. The next prime is 81445201. The reversal of 81445194 is 49154418.

It can be written as a sum of positive squares in only one way, i.e., 48233025 + 33212169 = 6945^2 + 5763^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2262349 + ... + 2262384.

Almost surely, 2^81445194 is an apocalyptic number.

81445194 is an abundant number, since it is smaller than the sum of its proper divisors (95019432).

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

81445194 is a wasteful number, since it uses less digits than its factorization.

81445194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4524741 (or 4524738 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81445194 is about 9024.6991085576. The cubic root of 81445194 is about 433.4661156531.

The spelling of 81445194 in words is "eighty-one million, four hundred forty-five thousand, one hundred ninety-four".