221957 has 2 divisors, whose sum is σ = 221958. Its totient is φ = 221956.

The previous prime is 221953. The next prime is 221987. The reversal of 221957 is 759122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 164836 + 57121 = 406^2 + 239^2 .

It is a cyclic number.

It is not a de Polignac number, because 221957 - 2² = 221953 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110978 + 110979.

It is an arithmetic number, because the mean of its divisors is an integer number (110979).

2²²¹⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

221957 is a deficient number, since it is larger than the sum of its proper divisors (1).

221957 is an equidigital number, since it uses as much as digits as its factorization.

221957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1260, while the sum is 26.

The square root of 221957 is about 471.1231261571. The cubic root of 221957 is about 60.5465797967.

The spelling of 221957 in words is "two hundred twenty-one thousand, nine hundred fifty-seven".