21352649 has 2 divisors, whose sum is σ = 21352650. Its totient is φ = 21352648.

The previous prime is 21352627. The next prime is 21352651. The reversal of 21352649 is 94625312.

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., 16321600 + 5031049 = 4040^2 + 2243^2 .

It is a cyclic number.

It is not a de Polignac number, because 21352649 - 2⁸ = 21352393 is a prime.

Together with 21352651, 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 (21352609) 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, 10676324 + 10676325.

It is an arithmetic number, because the mean of its divisors is an integer number (10676325).

Almost surely, 2^21352649 is an apocalyptic number.

It is an amenable number.

21352649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352649 is an equidigital number, since it uses as much as digits as its factorization.

21352649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 32.

The square root of 21352649 is about 4620.8926626789. The cubic root of 21352649 is about 277.4281890856.

The spelling of 21352649 in words is "twenty-one million, three hundred fifty-two thousand, six hundred forty-nine".