81645383 has 4 divisors (see below), whose sum is σ = 81684648. Its totient is φ = 81606120.

The previous prime is 81645371. The next prime is 81645397. The reversal of 81645383 is 38354618.

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 81645383 - 2⁴ = 81645367 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 (81645323) 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, 16328 + ... + 20733.

It is an arithmetic number, because the mean of its divisors is an integer number (20421162).

Almost surely, 2^81645383 is an apocalyptic number.

81645383 is a deficient number, since it is larger than the sum of its proper divisors (39265).

81645383 is a wasteful number, since it uses less digits than its factorization.

81645383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39264.

The product of its digits is 69120, while the sum is 38.

The square root of 81645383 is about 9035.7834746081. The cubic root of 81645383 is about 433.8209724768.

It can be divided in two parts, 81645 and 383, that added together give a palindrome (82028).

The spelling of 81645383 in words is "eighty-one million, six hundred forty-five thousand, three hundred eighty-three".