81203616 has 216 divisors, whose sum is σ = 266309316. Its totient is φ = 23316480.

The previous prime is 81203533. The next prime is 81203621. The reversal of 81203616 is 61630218.

It can be written as a sum of positive squares in 2 ways, for example, as 64064016 + 17139600 = 8004^2 + 4140^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81203616.

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 35 ways as a sum of consecutive naturals, for example, 1980556 + ... + 1980596.

Almost surely, 2^81203616 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 81203616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133154658).

81203616 is an abundant number, since it is smaller than the sum of its proper divisors (185105700).

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

81203616 is a wasteful number, since it uses less digits than its factorization.

81203616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81203616 is about 9011.3048999576. The cubic root of 81203616 is about 433.0371172181.

The spelling of 81203616 in words is "eighty-one million, two hundred three thousand, six hundred sixteen".