81416664 has 192 divisors, whose sum is σ = 271165440. Its totient is φ = 22394880.

The previous prime is 81416663. The next prime is 81416669. The reversal of 81416664 is 46661418.

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 (81416663) 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 47 ways as a sum of consecutive naturals, for example, 421752 + ... + 421944.

It is an arithmetic number, because the mean of its divisors is an integer number (1412320).

Almost surely, 2^81416664 is an apocalyptic number.

81416664 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81416664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135582720).

81416664 is an abundant number, since it is smaller than the sum of its proper divisors (189748776).

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

81416664 is a wasteful number, since it uses less digits than its factorization.

81416664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 236 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 81416664 is about 9023.1183079909. The cubic root of 81416664 is about 433.4154957946.

The spelling of 81416664 in words is "eighty-one million, four hundred sixteen thousand, six hundred sixty-four".