84731221 has 4 divisors (see below), whose sum is σ = 87021292. Its totient is φ = 82441152.

The previous prime is 84731219. The next prime is 84731233. The reversal of 84731221 is 12213748.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 57168721 + 27562500 = 7561^2 + 5250^2 .

It is a cyclic number.

It is not a de Polignac number, because 84731221 - 2¹ = 84731219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 84731221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84731921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1144980 + ... + 1145053.

It is an arithmetic number, because the mean of its divisors is an integer number (21755323).

Almost surely, 2^84731221 is an apocalyptic number.

It is an amenable number.

84731221 is a deficient number, since it is larger than the sum of its proper divisors (2290071).

84731221 is a wasteful number, since it uses less digits than its factorization.

84731221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290070.

The product of its digits is 2688, while the sum is 28.

The square root of 84731221 is about 9204.9563279790. The cubic root of 84731221 is about 439.2190365066.

Adding to 84731221 its reverse (12213748), we get a palindrome (96944969).

The spelling of 84731221 in words is "eighty-four million, seven hundred thirty-one thousand, two hundred twenty-one".