21414257 has 2 divisors, whose sum is σ = 21414258. Its totient is φ = 21414256.

The previous prime is 21414241. The next prime is 21414269. The reversal of 21414257 is 75241412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16613776 + 4800481 = 4076^2 + 2191^2 .

It is a cyclic number.

It is not a de Polignac number, because 21414257 - 2⁴ = 21414241 is a prime.

It is a super-3 number, since 3×21414257³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21414277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707128 + 10707129.

It is an arithmetic number, because the mean of its divisors is an integer number (10707129).

Almost surely, 2^21414257 is an apocalyptic number.

It is an amenable number.

21414257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21414257 is an equidigital number, since it uses as much as digits as its factorization.

21414257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2240, while the sum is 26.

The square root of 21414257 is about 4627.5541055724. The cubic root of 21414257 is about 277.6947506110.

Adding to 21414257 its reverse (75241412), we get a palindrome (96655669).

The spelling of 21414257 in words is "twenty-one million, four hundred fourteen thousand, two hundred fifty-seven".