81769231 has 4 divisors (see below), whose sum is σ = 81791464. Its totient is φ = 81747000.

The previous prime is 81769153. The next prime is 81769243. The reversal of 81769231 is 13296718.

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 81769231 - 2¹⁵ = 81736463 is a prime.

It is a super-4 number, since 4×81769231⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81769291) 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, 4140 + ... + 13441.

It is an arithmetic number, because the mean of its divisors is an integer number (20447866).

Almost surely, 2^81769231 is an apocalyptic number.

81769231 is a deficient number, since it is larger than the sum of its proper divisors (22233).

81769231 is a wasteful number, since it uses less digits than its factorization.

81769231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22232.

The product of its digits is 18144, while the sum is 37.

The square root of 81769231 is about 9042.6340742065. The cubic root of 81769231 is about 434.0402162114.

The spelling of 81769231 in words is "eighty-one million, seven hundred sixty-nine thousand, two hundred thirty-one".