81317502 has 48 divisors (see below), whose sum is σ = 202849920. Its totient is φ = 23061456.

The previous prime is 81317491. The next prime is 81317521. The reversal of 81317502 is 20571318.

It is a super-2 number, since 2×81317502² = 13225072263040008, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15193 + ... + 19835.

It is an arithmetic number, because the mean of its divisors is an integer number (4226040).

Almost surely, 2^81317502 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81317502, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101424960).

81317502 is an abundant number, since it is smaller than the sum of its proper divisors (121532418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81317502 is a wasteful number, since it uses less digits than its factorization.

81317502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4797 (or 4794 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 81317502 is about 9017.6217485543. The cubic root of 81317502 is about 433.2394638224.

The spelling of 81317502 in words is "eighty-one million, three hundred seventeen thousand, five hundred two".