81382783 has 4 divisors (see below), whose sum is σ = 81571168. Its totient is φ = 81194400.

The previous prime is 81382753. The next prime is 81382811. The reversal of 81382783 is 38728318.

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 81382783 - 2⁵ = 81382751 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 (81382753) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93543 + ... + 94408.

It is an arithmetic number, because the mean of its divisors is an integer number (20392792).

Almost surely, 2^81382783 is an apocalyptic number.

81382783 is a deficient number, since it is larger than the sum of its proper divisors (188385).

81382783 is a wasteful number, since it uses less digits than its factorization.

81382783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188384.

The product of its digits is 64512, while the sum is 40.

The square root of 81382783 is about 9021.2406574706. The cubic root of 81382783 is about 433.3553664668.

The spelling of 81382783 in words is "eighty-one million, three hundred eighty-two thousand, seven hundred eighty-three".