81237815 has 16 divisors (see below), whose sum is σ = 103511520. Its totient is φ = 60994560.

The previous prime is 81237811. The next prime is 81237823. The reversal of 81237815 is 51873218.

It is not a de Polignac number, because 81237815 - 2² = 81237811 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81237811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34475 + ... + 36755.

It is an arithmetic number, because the mean of its divisors is an integer number (6469470).

Almost surely, 2^81237815 is an apocalyptic number.

81237815 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

81237815 is a deficient number, since it is larger than the sum of its proper divisors (22273705).

81237815 is a wasteful number, since it uses less digits than its factorization.

81237815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722.

The product of its digits is 13440, while the sum is 35.

The square root of 81237815 is about 9013.2022611278. The cubic root of 81237815 is about 433.0979000526.

The spelling of 81237815 in words is "eighty-one million, two hundred thirty-seven thousand, eight hundred fifteen".