81316916 has 12 divisors (see below), whose sum is σ = 150675588. Its totient is φ = 38266752.

The previous prime is 81316889. The next prime is 81316919. The reversal of 81316916 is 61961318.

It can be written as a sum of positive squares in 2 ways, for example, as 34339600 + 46977316 = 5860^2 + 6854^2 .

It is a super-2 number, since 2×81316916² = 13224881655502112, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81316919) 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, 597851 + ... + 597986.

It is an arithmetic number, because the mean of its divisors is an integer number (12556299).

Almost surely, 2^81316916 is an apocalyptic number.

It is an amenable number.

81316916 is a deficient number, since it is larger than the sum of its proper divisors (69358672).

81316916 is a wasteful number, since it uses less digits than its factorization.

81316916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1195858 (or 1195856 counting only the distinct ones).

The product of its digits is 7776, while the sum is 35.

The square root of 81316916 is about 9017.5892565585. The cubic root of 81316916 is about 433.2384231324.

The spelling of 81316916 in words is "eighty-one million, three hundred sixteen thousand, nine hundred sixteen".