81216446 has 16 divisors (see below), whose sum is σ = 129321360. Its totient is φ = 38121600.

The previous prime is 81216439. The next prime is 81216461. The reversal of 81216446 is 64461218.

It is a super-2 number, since 2×81216446² = 13192222201741832, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11396 + ... + 17096.

It is an arithmetic number, because the mean of its divisors is an integer number (8082585).

Almost surely, 2^81216446 is an apocalyptic number.

81216446 is a deficient number, since it is larger than the sum of its proper divisors (48104914).

81216446 is a wasteful number, since it uses less digits than its factorization.

81216446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6139.

The product of its digits is 9216, while the sum is 32.

The square root of 81216446 is about 9012.0167554216. The cubic root of 81216446 is about 433.0599223341.

The spelling of 81216446 in words is "eighty-one million, two hundred sixteen thousand, four hundred forty-six".