81248540 has 24 divisors (see below), whose sum is σ = 171180240. Its totient is φ = 32393088.

The previous prime is 81248539. The next prime is 81248567. The reversal of 81248540 is 4584218.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81248497 and 81248506.

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, 230 + ... + 12749.

It is an arithmetic number, because the mean of its divisors is an integer number (7132510).

Almost surely, 2^81248540 is an apocalyptic number.

It is an amenable number.

81248540 is an abundant number, since it is smaller than the sum of its proper divisors (89931700).

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

81248540 is a wasteful number, since it uses less digits than its factorization.

81248540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13301 (or 13299 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 32.

The square root of 81248540 is about 9013.7972020675. The cubic root of 81248540 is about 433.1169583798.

The spelling of 81248540 in words is "eighty-one million, two hundred forty-eight thousand, five hundred forty".