81294418 has 4 divisors (see below), whose sum is σ = 121941630. Its totient is φ = 40647208.

The previous prime is 81294413. The next prime is 81294419. The reversal of 81294418 is 81449218.

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., 80514729 + 779689 = 8973^2 + 883^2 .

It is not an unprimeable number, because it can be changed into a prime (81294413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20323603 + ... + 20323606.

Almost surely, 2^81294418 is an apocalyptic number.

81294418 is a deficient number, since it is larger than the sum of its proper divisors (40647212).

81294418 is a wasteful number, since it uses less digits than its factorization.

81294418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40647211.

The product of its digits is 18432, while the sum is 37.

The square root of 81294418 is about 9016.3417193449. The cubic root of 81294418 is about 433.1984646688.

The spelling of 81294418 in words is "eighty-one million, two hundred ninety-four thousand, four hundred eighteen".