81238515 has 8 divisors (see below), whose sum is σ = 129981648. Its totient is φ = 43327200.

The previous prime is 81238501. The next prime is 81238523. The reversal of 81238515 is 51583218.

It is a happy number.

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

It is not a de Polignac number, because 81238515 - 2⁴ = 81238499 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2707936 + ... + 2707965.

It is an arithmetic number, because the mean of its divisors is an integer number (16247706).

Almost surely, 2^81238515 is an apocalyptic number.

81238515 is a deficient number, since it is larger than the sum of its proper divisors (48743133).

81238515 is a wasteful number, since it uses less digits than its factorization.

81238515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5415909.

The product of its digits is 9600, while the sum is 33.

The square root of 81238515 is about 9013.2410929698. The cubic root of 81238515 is about 433.0991440039.

The spelling of 81238515 in words is "eighty-one million, two hundred thirty-eight thousand, five hundred fifteen".