81249994 has 16 divisors (see below), whose sum is σ = 139741056. Its totient is φ = 34707600.

The previous prime is 81249979. The next prime is 81249997. The reversal of 81249994 is 49994218.

It is not an unprimeable number, because it can be changed into a prime (81249997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4977 + ... + 13684.

It is an arithmetic number, because the mean of its divisors is an integer number (8733816).

Almost surely, 2^81249994 is an apocalyptic number.

81249994 is a deficient number, since it is larger than the sum of its proper divisors (58491062).

81249994 is a wasteful number, since it uses less digits than its factorization.

81249994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18981.

The product of its digits is 186624, while the sum is 46.

The square root of 81249994 is about 9013.8778558398. The cubic root of 81249994 is about 433.1195420090.

The spelling of 81249994 in words is "eighty-one million, two hundred forty-nine thousand, nine hundred ninety-four".