857221 has 2 divisors, whose sum is σ = 857222. Its totient is φ = 857220.

The previous prime is 857203. The next prime is 857249. The reversal of 857221 is 122758.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 448900 + 408321 = 670^2 + 639^2 .

It is a cyclic number.

It is not a de Polignac number, because 857221 - 2¹⁷ = 726149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (857201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428610 + 428611.

It is an arithmetic number, because the mean of its divisors is an integer number (428611).

2⁸⁵⁷²²¹ is an apocalyptic number.

It is an amenable number.

857221 is a deficient number, since it is larger than the sum of its proper divisors (1).

857221 is an equidigital number, since it uses as much as digits as its factorization.

857221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1120, while the sum is 25.

The square root of 857221 is about 925.8623007770. The cubic root of 857221 is about 94.9943117554.

Adding to 857221 its reverse (122758), we get a palindrome (979979).

The spelling of 857221 in words is "eight hundred fifty-seven thousand, two hundred twenty-one".