81622816 has 48 divisors (see below), whose sum is σ = 176033088. Its totient is φ = 36947200.

The previous prime is 81622811. The next prime is 81622859. The reversal of 81622816 is 61822618.

It is not an unprimeable number, because it can be changed into a prime (81622811) 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, 162021 + ... + 162523.

It is an arithmetic number, because the mean of its divisors is an integer number (3667356).

Almost surely, 2^81622816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81622816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88016544).

81622816 is an abundant number, since it is smaller than the sum of its proper divisors (94410272).

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

81622816 is a wasteful number, since it uses less digits than its factorization.

81622816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 985 (or 977 counting only the distinct ones).

The product of its digits is 9216, while the sum is 34.

The square root of 81622816 is about 9034.5346310698. The cubic root of 81622816 is about 433.7809990386.

It can be divided in two parts, 816 and 22816, that added together give a palindrome (23632).

The spelling of 81622816 in words is "eighty-one million, six hundred twenty-two thousand, eight hundred sixteen".