82143821 has 4 divisors (see below), whose sum is σ = 86467200. Its totient is φ = 77820444.

The previous prime is 82143797. The next prime is 82143823. The reversal of 82143821 is 12834128.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82143821 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 (82143823) 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, 2161661 + ... + 2161698.

It is an arithmetic number, because the mean of its divisors is an integer number (21616800).

Almost surely, 2^82143821 is an apocalyptic number.

It is an amenable number.

82143821 is a deficient number, since it is larger than the sum of its proper divisors (4323379).

82143821 is a wasteful number, since it uses less digits than its factorization.

82143821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4323378.

The product of its digits is 3072, while the sum is 29.

The square root of 82143821 is about 9063.3228454028. The cubic root of 82143821 is about 434.7019952147.

Adding to 82143821 its reverse (12834128), we get a palindrome (94977949).

The spelling of 82143821 in words is "eighty-two million, one hundred forty-three thousand, eight hundred twenty-one".