81421600 has 72 divisors (see below), whose sum is σ = 214087860. Its totient is φ = 30059520.

The previous prime is 81421579. The next prime is 81421649. The reversal of 81421600 is 612418.

It can be written as a sum of positive squares in 6 ways, for example, as 4613904 + 76807696 = 2148^2 + 8764^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6486 + ... + 14314.

Almost surely, 2^81421600 is an apocalyptic number.

81421600 is a gapful number since it is divisible by the number (80) 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 81421600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107043930).

81421600 is an abundant number, since it is smaller than the sum of its proper divisors (132666260).

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

81421600 is a wasteful number, since it uses less digits than its factorization.

81421600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7862 (or 7849 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 81421600 is about 9023.3918234775. The cubic root of 81421600 is about 433.4242544261.

The spelling of 81421600 in words is "eighty-one million, four hundred twenty-one thousand, six hundred".