999993221 has 2 divisors, whose sum is σ = 999993222. Its totient is φ = 999993220.

The previous prime is 999993179. The next prime is 999993229. The reversal of 999993221 is 122399999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 885717121 + 114276100 = 29761^2 + 10690^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999993221 is a prime.

It is a Chen prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999993229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499996610 + 499996611.

It is an arithmetic number, because the mean of its divisors is an integer number (499996611).

Almost surely, 2^999993221 is an apocalyptic number.

It is an amenable number.

999993221 is a deficient number, since it is larger than the sum of its proper divisors (1).

999993221 is an equidigital number, since it uses as much as digits as its factorization.

999993221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 708588, while the sum is 53.

The square root of 999993221 is about 31622.6694161008. The cubic root of 999993221 is about 999.9977403282.

The spelling of 999993221 in words is "nine hundred ninety-nine million, nine hundred ninety-three thousand, two hundred twenty-one".