81815235 has 48 divisors (see below), whose sum is σ = 143195040. Its totient is φ = 39836160.

The previous prime is 81815233. The next prime is 81815257. The reversal of 81815235 is 53251818.

It is a happy number.

It is not a de Polignac number, because 81815235 - 2¹ = 81815233 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81815196 and 81815205.

It is not an unprimeable number, because it can be changed into a prime (81815233) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 156775 + ... + 157295.

It is an arithmetic number, because the mean of its divisors is an integer number (2983230).

Almost surely, 2^81815235 is an apocalyptic number.

81815235 is a deficient number, since it is larger than the sum of its proper divisors (61379805).

81815235 is a wasteful number, since it uses less digits than its factorization.

81815235 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596 (or 577 counting only the distinct ones).

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

The square root of 81815235 is about 9045.1774443623. The cubic root of 81815235 is about 434.1215990755.

The spelling of 81815235 in words is "eighty-one million, eight hundred fifteen thousand, two hundred thirty-five".