81339930 has 64 divisors (see below), whose sum is σ = 247898880. Its totient is φ = 18591552.

The previous prime is 81339911. The next prime is 81339959. The reversal of 81339930 is 3993318.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19629 + ... + 23408.

It is an arithmetic number, because the mean of its divisors is an integer number (3873420).

Almost surely, 2^81339930 is an apocalyptic number.

81339930 is an abundant number, since it is smaller than the sum of its proper divisors (166558950).

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

81339930 is a wasteful number, since it uses less digits than its factorization.

81339930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43060 (or 43054 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 81339930 is about 9018.8652279541. The cubic root of 81339930 is about 433.2792904333.

The spelling of 81339930 in words is "eighty-one million, three hundred thirty-nine thousand, nine hundred thirty".