81216382 has 16 divisors (see below), whose sum is σ = 131371632. Its totient is φ = 37434240.

The previous prime is 81216353. The next prime is 81216383. The reversal of 81216382 is 28361218.

It is a super-2 number, since 2×81216382² = 13192201410339848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81216383) 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, 23638 + ... + 26854.

It is an arithmetic number, because the mean of its divisors is an integer number (8210727).

Almost surely, 2^81216382 is an apocalyptic number.

81216382 is a deficient number, since it is larger than the sum of its proper divisors (50155250).

81216382 is a wasteful number, since it uses less digits than its factorization.

81216382 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4203.

The product of its digits is 4608, while the sum is 31.

The square root of 81216382 is about 9012.0132046064. The cubic root of 81216382 is about 433.0598085811.

The spelling of 81216382 in words is "eighty-one million, two hundred sixteen thousand, three hundred eighty-two".