21545353 has 2 divisors, whose sum is σ = 21545354. Its totient is φ = 21545352.

The previous prime is 21545351. The next prime is 21545357. The reversal of 21545353 is 35354512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11641744 + 9903609 = 3412^2 + 3147^2 .

It is a cyclic number.

It is not a de Polignac number, because 21545353 - 2¹ = 21545351 is a prime.

Together with 21545351, it forms a pair of twin primes.

It is equal to p_1362259 and since 21545353 and 1362259 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21545351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772676 + 10772677.

It is an arithmetic number, because the mean of its divisors is an integer number (10772677).

Almost surely, 2^21545353 is an apocalyptic number.

It is an amenable number.

21545353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21545353 is an equidigital number, since it uses as much as digits as its factorization.

21545353 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9000, while the sum is 28.

The square root of 21545353 is about 4641.6972111502. The cubic root of 21545353 is about 278.2602715790.

Adding to 21545353 its reverse (35354512), we get a palindrome (56899865).

The spelling of 21545353 in words is "twenty-one million, five hundred forty-five thousand, three hundred fifty-three".