81653111 has 4 divisors (see below), whose sum is σ = 81732000. Its totient is φ = 81574224.

The previous prime is 81653107. The next prime is 81653119. The reversal of 81653111 is 11135618.

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

It is a cyclic number.

It is not a de Polignac number, because 81653111 - 2² = 81653107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81653119) 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, 37871 + ... + 39968.

It is an arithmetic number, because the mean of its divisors is an integer number (20433000).

Almost surely, 2^81653111 is an apocalyptic number.

81653111 is a deficient number, since it is larger than the sum of its proper divisors (78889).

81653111 is a wasteful number, since it uses less digits than its factorization.

81653111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78888.

The product of its digits is 720, while the sum is 26.

The square root of 81653111 is about 9036.2110975785. The cubic root of 81653111 is about 433.8346595651.

Adding to 81653111 its reverse (11135618), we get a palindrome (92788729).

The spelling of 81653111 in words is "eighty-one million, six hundred fifty-three thousand, one hundred eleven".