82173921 has 4 divisors (see below), whose sum is σ = 109565232. Its totient is φ = 54782612.

The previous prime is 82173919. The next prime is 82173941. The reversal of 82173921 is 12937128.

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 not a de Polignac number, because 82173921 - 2¹ = 82173919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (82173941) 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, 13695651 + ... + 13695656.

It is an arithmetic number, because the mean of its divisors is an integer number (27391308).

Almost surely, 2^82173921 is an apocalyptic number.

It is an amenable number.

82173921 is a deficient number, since it is larger than the sum of its proper divisors (27391311).

82173921 is a wasteful number, since it uses less digits than its factorization.

82173921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27391310.

The product of its digits is 6048, while the sum is 33.

The square root of 82173921 is about 9064.9832321963. The cubic root of 82173921 is about 434.7550847514.

The spelling of 82173921 in words is "eighty-two million, one hundred seventy-three thousand, nine hundred twenty-one".