81301615 has 4 divisors (see below), whose sum is σ = 97561944. Its totient is φ = 65041288.

The previous prime is 81301609. The next prime is 81301631. The reversal of 81301615 is 51610318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81301615 - 2¹¹ = 81299567 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81301615.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8130157 + ... + 8130166.

It is an arithmetic number, because the mean of its divisors is an integer number (24390486).

Almost surely, 2^81301615 is an apocalyptic number.

81301615 is a deficient number, since it is larger than the sum of its proper divisors (16260329).

81301615 is a wasteful number, since it uses less digits than its factorization.

81301615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16260328.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 81301615 is about 9016.7408191652. The cubic root of 81301615 is about 433.2112479875.

The spelling of 81301615 in words is "eighty-one million, three hundred one thousand, six hundred fifteen".