81237816 has 192 divisors, whose sum is σ = 259459200. Its totient is φ = 23587200.

The previous prime is 81237811. The next prime is 81237823. The reversal of 81237816 is 61873218.

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

Its product of digits (16128) is a multiple of the sum of its prime factors (192).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81237811) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 620071 + ... + 620201.

It is an arithmetic number, because the mean of its divisors is an integer number (1351350).

Almost surely, 2^81237816 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 81237816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129729600).

81237816 is an abundant number, since it is smaller than the sum of its proper divisors (178221384).

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

81237816 is a wasteful number, since it uses less digits than its factorization.

81237816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 176 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 81237816 is about 9013.2023166020. The cubic root of 81237816 is about 433.0979018297.

The spelling of 81237816 in words is "eighty-one million, two hundred thirty-seven thousand, eight hundred sixteen".