81530340 has 48 divisors (see below), whose sum is σ = 228959808. Its totient is φ = 21677184.

The previous prime is 81530333. The next prime is 81530363. The reversal of 81530340 is 4303518.

It is a self number, because there is not a number n which added to its sum of digits gives 81530340.

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 15 ways as a sum of consecutive naturals, for example, 20559 + ... + 24201.

It is an arithmetic number, because the mean of its divisors is an integer number (4769996).

Almost surely, 2^81530340 is an apocalyptic number.

It is an amenable number.

81530340 is an abundant number, since it is smaller than the sum of its proper divisors (147429468).

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

81530340 is a wasteful number, since it uses less digits than its factorization.

81530340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4028 (or 4026 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 81530340 is about 9029.4152634598. The cubic root of 81530340 is about 433.6171172035.

Adding to 81530340 its reverse (4303518), we get a palindrome (85833858).

The spelling of 81530340 in words is "eighty-one million, five hundred thirty thousand, three hundred forty".