21141257 has 2 divisors, whose sum is σ = 21141258. Its totient is φ = 21141256.

The previous prime is 21141233. The next prime is 21141259. The reversal of 21141257 is 75214112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15241216 + 5900041 = 3904^2 + 2429^2 .

It is a cyclic number.

It is not a de Polignac number, because 21141257 - 2¹⁸ = 20879113 is a prime.

Together with 21141259, 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 (21141259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570628 + 10570629.

It is an arithmetic number, because the mean of its divisors is an integer number (10570629).

Almost surely, 2^21141257 is an apocalyptic number.

It is an amenable number.

21141257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21141257 is an equidigital number, since it uses as much as digits as its factorization.

21141257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 560, while the sum is 23.

The square root of 21141257 is about 4597.9622660479. The cubic root of 21141257 is about 276.5096347633.

Adding to 21141257 its reverse (75214112), we get a palindrome (96355369).

The spelling of 21141257 in words is "twenty-one million, one hundred forty-one thousand, two hundred fifty-seven".