21241457 has 2 divisors, whose sum is σ = 21241458. Its totient is φ = 21241456.

The previous prime is 21241453. The next prime is 21241469. The reversal of 21241457 is 75414212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20784481 + 456976 = 4559^2 + 676^2 .

It is a cyclic number.

It is not a de Polignac number, because 21241457 - 2² = 21241453 is a prime.

It is not a weakly prime, because it can be changed into another prime (21241453) 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, 10620728 + 10620729.

It is an arithmetic number, because the mean of its divisors is an integer number (10620729).

Almost surely, 2^21241457 is an apocalyptic number.

It is an amenable number.

21241457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241457 is an equidigital number, since it uses as much as digits as its factorization.

21241457 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 21241457 is about 4608.8455170465. The cubic root of 21241457 is about 276.9457899798.

Adding to 21241457 its reverse (75414212), we get a palindrome (96655669).

The spelling of 21241457 in words is "twenty-one million, two hundred forty-one thousand, four hundred fifty-seven".