84971221 has 2 divisors, whose sum is σ = 84971222. Its totient is φ = 84971220.

The previous prime is 84971213. The next prime is 84971233. The reversal of 84971221 is 12217948.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80748196 + 4223025 = 8986^2 + 2055^2 .

It is a cyclic number.

It is not a de Polignac number, because 84971221 - 2³ = 84971213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84971291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42485610 + 42485611.

It is an arithmetic number, because the mean of its divisors is an integer number (42485611).

Almost surely, 2^84971221 is an apocalyptic number.

It is an amenable number.

84971221 is a deficient number, since it is larger than the sum of its proper divisors (1).

84971221 is an equidigital number, since it uses as much as digits as its factorization.

84971221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 34.

The square root of 84971221 is about 9217.9835647499. The cubic root of 84971221 is about 439.6333395121.

The spelling of 84971221 in words is "eighty-four million, nine hundred seventy-one thousand, two hundred twenty-one".