81624816 has 120 divisors (see below), whose sum is σ = 281197280. Its totient is φ = 21523968.

The previous prime is 81624811. The next prime is 81624857. The reversal of 81624816 is 61842618.

It is a super-2 number, since 2×81624816² = 13325221174067712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81624811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9990 + ... + 16218.

Almost surely, 2^81624816 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 81624816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140598640).

81624816 is an abundant number, since it is smaller than the sum of its proper divisors (199572464).

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

81624816 is a wasteful number, since it uses less digits than its factorization.

81624816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6263 (or 6254 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 81624816 is about 9034.6453167792. The cubic root of 81624816 is about 433.7845419814.

The spelling of 81624816 in words is "eighty-one million, six hundred twenty-four thousand, eight hundred sixteen".