81940994 has 8 divisors (see below), whose sum is σ = 122949900. Its totient is φ = 40957696.

The previous prime is 81940993. The next prime is 81941011. The reversal of 81940994 is 49904918.

It can be written as a sum of positive squares in 2 ways, for example, as 75463969 + 6477025 = 8687^2 + 2545^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (81940993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9482 + ... + 15930.

Almost surely, 2^81940994 is an apocalyptic number.

81940994 is a deficient number, since it is larger than the sum of its proper divisors (41008906).

81940994 is a wasteful number, since it uses less digits than its factorization.

81940994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12804.

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 81940994 is about 9052.1264904993. The cubic root of 81940994 is about 434.3439160615.

The spelling of 81940994 in words is "eighty-one million, nine hundred forty thousand, nine hundred ninety-four".