81515383 has 4 divisors (see below), whose sum is σ = 82322568. Its totient is φ = 80708200.

The previous prime is 81515353. The next prime is 81515429. The reversal of 81515383 is 38351518.

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 81515383 - 2¹⁷ = 81384311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81515353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 403441 + ... + 403642.

It is an arithmetic number, because the mean of its divisors is an integer number (20580642).

Almost surely, 2^81515383 is an apocalyptic number.

81515383 is a deficient number, since it is larger than the sum of its proper divisors (807185).

81515383 is a wasteful number, since it uses less digits than its factorization.

81515383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807184.

The product of its digits is 14400, while the sum is 34.

The square root of 81515383 is about 9028.5869880065. The cubic root of 81515383 is about 433.5905994357.

The spelling of 81515383 in words is "eighty-one million, five hundred fifteen thousand, three hundred eighty-three".