81216198 has 48 divisors (see below), whose sum is σ = 201745440. Its totient is φ = 23131008.

The previous prime is 81216133. The next prime is 81216199. The reversal of 81216198 is 89161218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81216199) 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 23 ways as a sum of consecutive naturals, for example, 48186 + ... + 49842.

It is an arithmetic number, because the mean of its divisors is an integer number (4203030).

Almost surely, 2^81216198 is an apocalyptic number.

81216198 is an abundant number, since it is smaller than the sum of its proper divisors (120529242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81216198 is a wasteful number, since it uses less digits than its factorization.

81216198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2061 (or 2058 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 81216198 is about 9012.0029960048. The cubic root of 81216198 is about 433.0594815409.

The spelling of 81216198 in words is "eighty-one million, two hundred sixteen thousand, one hundred ninety-eight".