81769999 has 4 divisors (see below), whose sum is σ = 81794664. Its totient is φ = 81745336.

The previous prime is 81769997. The next prime is 81770009. The reversal of 81769999 is 99996718.

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 81769999 - 2¹ = 81769997 is a prime.

It is a Duffinian number.

81769999 is a modest number, since divided by 9999 gives 8176 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81769993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6412 + ... + 14305.

It is an arithmetic number, because the mean of its divisors is an integer number (20448666).

Almost surely, 2^81769999 is an apocalyptic number.

81769999 is a deficient number, since it is larger than the sum of its proper divisors (24665).

81769999 is a wasteful number, since it uses less digits than its factorization.

81769999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24664.

The product of its digits is 2204496, while the sum is 58.

The square root of 81769999 is about 9042.6765396093. The cubic root of 81769999 is about 434.0415750838.

The spelling of 81769999 in words is "eighty-one million, seven hundred sixty-nine thousand, nine hundred ninety-nine".