81339915 has 8 divisors (see below), whose sum is σ = 130143888. Its totient is φ = 43381280.

The previous prime is 81339911. The next prime is 81339959. The reversal of 81339915 is 51993318.

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

It is not a de Polignac number, because 81339915 - 2² = 81339911 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81339911) 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, 2711316 + ... + 2711345.

It is an arithmetic number, because the mean of its divisors is an integer number (16267986).

Almost surely, 2^81339915 is an apocalyptic number.

81339915 is a deficient number, since it is larger than the sum of its proper divisors (48803973).

81339915 is a wasteful number, since it uses less digits than its factorization.

81339915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5422669.

The product of its digits is 29160, while the sum is 39.

The square root of 81339915 is about 9018.8643963639. The cubic root of 81339915 is about 433.2792637994.

The spelling of 81339915 in words is "eighty-one million, three hundred thirty-nine thousand, nine hundred fifteen".