84210221 has 4 divisors (see below), whose sum is σ = 84228732. Its totient is φ = 84191712.

The previous prime is 84210193. The next prime is 84210241. The reversal of 84210221 is 12201248.

It is a happy number.

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 71149225 + 13060996 = 8435^2 + 3614^2 .

It is a cyclic number.

It is not a de Polignac number, because 84210221 - 2⁶ = 84210157 is a prime.

It is a super-2 number, since 2×84210221² = 14182722641737682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 84210193 and 84210202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84210241) 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, 2825 + ... + 13281.

It is an arithmetic number, because the mean of its divisors is an integer number (21057183).

Almost surely, 2^84210221 is an apocalyptic number.

It is an amenable number.

84210221 is a deficient number, since it is larger than the sum of its proper divisors (18511).

84210221 is a wasteful number, since it uses less digits than its factorization.

84210221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18510.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 84210221 is about 9176.6127192990. The cubic root of 84210221 is about 438.3169536433.

Adding to 84210221 its reverse (12201248), we get a palindrome (96411469).

The spelling of 84210221 in words is "eighty-four million, two hundred ten thousand, two hundred twenty-one".