21325457 has 2 divisors, whose sum is σ = 21325458. Its totient is φ = 21325456.

The previous prime is 21325441. The next prime is 21325471. The reversal of 21325457 is 75452312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15713296 + 5612161 = 3964^2 + 2369^2 .

It is a cyclic number.

It is not a de Polignac number, because 21325457 - 2⁴ = 21325441 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21325477) 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, 10662728 + 10662729.

It is an arithmetic number, because the mean of its divisors is an integer number (10662729).

Almost surely, 2^21325457 is an apocalyptic number.

It is an amenable number.

21325457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21325457 is an equidigital number, since it uses as much as digits as its factorization.

21325457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8400, while the sum is 29.

The square root of 21325457 is about 4617.9494367089. The cubic root of 21325457 is about 277.3103733856.

Adding to 21325457 its reverse (75452312), we get a palindrome (96777769).

The spelling of 21325457 in words is "twenty-one million, three hundred twenty-five thousand, four hundred fifty-seven".