81810415 has 8 divisors (see below), whose sum is σ = 98274960. Its totient is φ = 65380032.

The previous prime is 81810373. The next prime is 81810419. The reversal of 81810415 is 51401818.

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

It is a cyclic number.

It is not a de Polignac number, because 81810415 - 2¹⁷ = 81679343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81810419) 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, 2934 + ... + 13123.

It is an arithmetic number, because the mean of its divisors is an integer number (12284370).

Almost surely, 2^81810415 is an apocalyptic number.

81810415 is a deficient number, since it is larger than the sum of its proper divisors (16464545).

81810415 is a wasteful number, since it uses less digits than its factorization.

81810415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17081.

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 81810415 is about 9044.9110001149. The cubic root of 81810415 is about 434.1130737391.

The spelling of 81810415 in words is "eighty-one million, eight hundred ten thousand, four hundred fifteen".