81619776 has 168 divisors, whose sum is σ = 276417024. Its totient is φ = 22533120.

The previous prime is 81619753. The next prime is 81619781. The reversal of 81619776 is 67791618.

It is a tau number, because it is divible by the number of its divisors (168).

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

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 124666 + ... + 125318.

Almost surely, 2^81619776 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 81619776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138208512).

81619776 is an abundant number, since it is smaller than the sum of its proper divisors (194797248).

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

81619776 is a wasteful number, since it uses less digits than its factorization.

81619776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709 (or 696 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 81619776 is about 9034.3663861944. The cubic root of 81619776 is about 433.7756136546.

The spelling of 81619776 in words is "eighty-one million, six hundred nineteen thousand, seven hundred seventy-six".