81316493 has 8 divisors (see below), whose sum is σ = 85378080. Its totient is φ = 77338800.

The previous prime is 81316481. The next prime is 81316567. The reversal of 81316493 is 39461318.

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 81316493 - 2¹⁰ = 81315469 is a prime.

It is a super-2 number, since 2×81316493² = 13224744067638098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81316453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18983 + ... + 22868.

It is an arithmetic number, because the mean of its divisors is an integer number (10672260).

Almost surely, 2^81316493 is an apocalyptic number.

It is an amenable number.

81316493 is a deficient number, since it is larger than the sum of its proper divisors (4061587).

81316493 is a wasteful number, since it uses less digits than its factorization.

81316493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41947.

The product of its digits is 15552, while the sum is 35.

The square root of 81316493 is about 9017.5658023660. The cubic root of 81316493 is about 433.2376719145.

The spelling of 81316493 in words is "eighty-one million, three hundred sixteen thousand, four hundred ninety-three".