81522611 has 4 divisors (see below), whose sum is σ = 81541032. Its totient is φ = 81504192.

The previous prime is 81522569. The next prime is 81522613. The reversal of 81522611 is 11622518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81522611 is a prime.

It is a super-2 number, since 2×81522611² = 13291872208514642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81522613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1880 + ... + 12906.

It is an arithmetic number, because the mean of its divisors is an integer number (20385258).

Almost surely, 2^81522611 is an apocalyptic number.

81522611 is a deficient number, since it is larger than the sum of its proper divisors (18421).

81522611 is a wasteful number, since it uses less digits than its factorization.

81522611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18420.

The product of its digits is 960, while the sum is 26.

The square root of 81522611 is about 9028.9872632538. The cubic root of 81522611 is about 433.6034146047.

The spelling of 81522611 in words is "eighty-one million, five hundred twenty-two thousand, six hundred eleven".