81315215 has 8 divisors (see below), whose sum is σ = 97968528. Its totient is φ = 64792000.

The previous prime is 81315191. The next prime is 81315229. The reversal of 81315215 is 51251318.

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 81315215 - 2¹⁴ = 81298831 is a prime.

It is a super-2 number, since 2×81315215² = 13224328380992450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31142 + ... + 33651.

It is an arithmetic number, because the mean of its divisors is an integer number (12246066).

Almost surely, 2^81315215 is an apocalyptic number.

81315215 is a deficient number, since it is larger than the sum of its proper divisors (16653313).

81315215 is a wasteful number, since it uses less digits than its factorization.

81315215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65049.

The product of its digits is 1200, while the sum is 26.

The square root of 81315215 is about 9017.4949403923. The cubic root of 81315215 is about 433.2354022616.

The spelling of 81315215 in words is "eighty-one million, three hundred fifteen thousand, two hundred fifteen".