81358216 has 16 divisors (see below), whose sum is σ = 152683740. Its totient is φ = 40642560.

The previous prime is 81358213. The next prime is 81358219. The reversal of 81358216 is 61285318.

It is an interprime number because it is at equal distance from previous prime (81358213) and next prime (81358219).

It can be written as a sum of positive squares in 2 ways, for example, as 74753316 + 6604900 = 8646^2 + 2570^2 .

It is not an unprimeable number, because it can be changed into a prime (81358213) 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 3 ways as a sum of consecutive naturals, for example, 6456 + ... + 14296.

Almost surely, 2^81358216 is an apocalyptic number.

It is an amenable number.

81358216 is a deficient number, since it is larger than the sum of its proper divisors (71325524).

81358216 is a wasteful number, since it uses less digits than its factorization.

81358216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9144 (or 9140 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 81358216 is about 9019.8789348860. The cubic root of 81358216 is about 433.3117564536.

The spelling of 81358216 in words is "eighty-one million, three hundred fifty-eight thousand, two hundred sixteen".