81317492 has 24 divisors (see below), whose sum is σ = 150192000. Its totient is φ = 38416896.

The previous prime is 81317491. The next prime is 81317521. The reversal of 81317492 is 29471318.

It is a super-2 number, since 2×81317492² = 13225069010340128, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81317491) 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, 32933 + ... + 35315.

It is an arithmetic number, because the mean of its divisors is an integer number (6258000).

Almost surely, 2^81317492 is an apocalyptic number.

It is an amenable number.

81317492 is a deficient number, since it is larger than the sum of its proper divisors (68874508).

81317492 is a wasteful number, since it uses less digits than its factorization.

81317492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2855 (or 2853 counting only the distinct ones).

The product of its digits is 12096, while the sum is 35.

The square root of 81317492 is about 9017.6211940844. The cubic root of 81317492 is about 433.2394460633.

The spelling of 81317492 in words is "eighty-one million, three hundred seventeen thousand, four hundred ninety-two".