81619648 has 56 divisors (see below), whose sum is σ = 177905664. Its totient is φ = 36844800.

The previous prime is 81619613. The next prime is 81619723. The reversal of 81619648 is 84691618.

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 7 ways as a sum of consecutive naturals, for example, 134161 + ... + 134767.

Almost surely, 2^81619648 is an apocalyptic number.

81619648 is a gapful number since it is divisible by the number (88) 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 81619648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88952832).

81619648 is an abundant number, since it is smaller than the sum of its proper divisors (96286016).

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

81619648 is a wasteful number, since it uses less digits than its factorization.

81619648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821 (or 811 counting only the distinct ones).

The product of its digits is 82944, while the sum is 43.

The square root of 81619648 is about 9034.3593021309. The cubic root of 81619648 is about 433.7753868987.

The spelling of 81619648 in words is "eighty-one million, six hundred nineteen thousand, six hundred forty-eight".