921257 has 2 divisors, whose sum is σ = 921258. Its totient is φ = 921256.

The previous prime is 921241. The next prime is 921259. The reversal of 921257 is 752129.

921257 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 583696 + 337561 = 764^2 + 581^2 .

It is a cyclic number.

It is not a de Polignac number, because 921257 - 2⁴ = 921241 is a prime.

Together with 921259, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (921259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460628 + 460629.

It is an arithmetic number, because the mean of its divisors is an integer number (460629).

2⁹²¹²⁵⁷ is an apocalyptic number.

It is an amenable number.

921257 is a deficient number, since it is larger than the sum of its proper divisors (1).

921257 is an equidigital number, since it uses as much as digits as its factorization.

921257 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 921257 is about 959.8213375415. The cubic root of 921257 is about 97.3031575417.

The spelling of 921257 in words is "nine hundred twenty-one thousand, two hundred fifty-seven".