81813783 has 8 divisors (see below), whose sum is σ = 113827968. Its totient is φ = 52171064.

The previous prime is 81813769. The next prime is 81813803. The reversal of 81813783 is 38731818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81813783 - 2¹⁴ = 81797399 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81813703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 592785 + ... + 592922.

It is an arithmetic number, because the mean of its divisors is an integer number (14228496).

Almost surely, 2^81813783 is an apocalyptic number.

81813783 is a deficient number, since it is larger than the sum of its proper divisors (32014185).

81813783 is a wasteful number, since it uses less digits than its factorization.

81813783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185733.

The product of its digits is 32256, while the sum is 39.

The square root of 81813783 is about 9045.0971802408. The cubic root of 81813783 is about 434.1190308974.

The spelling of 81813783 in words is "eighty-one million, eight hundred thirteen thousand, seven hundred eighty-three".