21353459 has 2 divisors, whose sum is σ = 21353460. Its totient is φ = 21353458.

The previous prime is 21353443. The next prime is 21353461. The reversal of 21353459 is 95435312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21353459 - 2⁴ = 21353443 is a prime.

It is a super-2 number, since 2×21353459² = 911940422529362, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 21353461, 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 (21353419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676729 + 10676730.

It is an arithmetic number, because the mean of its divisors is an integer number (10676730).

Almost surely, 2^21353459 is an apocalyptic number.

21353459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21353459 is an equidigital number, since it uses as much as digits as its factorization.

21353459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 32.

The square root of 21353459 is about 4620.9803072508. The cubic root of 21353459 is about 277.4316970656.

It can be divided in two parts, 21353 and 459, that added together give a palindrome (21812).

The spelling of 21353459 in words is "twenty-one million, three hundred fifty-three thousand, four hundred fifty-nine".