8181994 has 4 divisors (see below), whose sum is σ = 12272994. Its totient is φ = 4090996.

The previous prime is 8181983. The next prime is 8182003. The reversal of 8181994 is 4991818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 6943225 + 1238769 = 2635^2 + 1113^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2045497 + ... + 2045500.

Almost surely, 2^8181994 is an apocalyptic number.

8181994 is a deficient number, since it is larger than the sum of its proper divisors (4091000).

8181994 is a wasteful number, since it uses less digits than its factorization.

8181994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4090999.

The product of its digits is 20736, while the sum is 40.

The square root of 8181994 is about 2860.4185008491. The cubic root of 8181994 is about 201.5052592182.

The spelling of 8181994 in words is "eight million, one hundred eighty-one thousand, nine hundred ninety-four".