81111380 has 48 divisors (see below), whose sum is σ = 204919680. Its totient is φ = 26345088.

The previous prime is 81111379. The next prime is 81111419. The reversal of 81111380 is 8311118.

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 15 ways as a sum of consecutive naturals, for example, 12587 + ... + 17906.

It is an arithmetic number, because the mean of its divisors is an integer number (4269160).

Almost surely, 2^81111380 is an apocalyptic number.

It is an amenable number.

81111380 is an abundant number, since it is smaller than the sum of its proper divisors (123808300).

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

81111380 is a wasteful number, since it uses less digits than its factorization.

81111380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30528 (or 30526 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 23.

The square root of 81111380 is about 9006.1856520949. The cubic root of 81111380 is about 432.8730984804.

Adding to 81111380 its reverse (8311118), we get a palindrome (89422498).

The spelling of 81111380 in words is "eighty-one million, one hundred eleven thousand, three hundred eighty".