81603520 has 56 divisors (see below), whose sum is σ = 195242688. Its totient is φ = 32486400.

The previous prime is 81603497. The next prime is 81603541. The reversal of 81603520 is 2530618.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 86250 + ... + 87190.

Almost surely, 2^81603520 is an apocalyptic number.

81603520 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 81603520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97621344).

81603520 is an abundant number, since it is smaller than the sum of its proper divisors (113639168).

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

81603520 is a wasteful number, since it uses less digits than its factorization.

81603520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1229 (or 1219 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 81603520 is about 9033.4666656827. The cubic root of 81603520 is about 433.7468137530.

The spelling of 81603520 in words is "eighty-one million, six hundred three thousand, five hundred twenty".