21453611 has 2 divisors, whose sum is σ = 21453612. Its totient is φ = 21453610.

The previous prime is 21453583. The next prime is 21453613. The reversal of 21453611 is 11635412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21453611 is a prime.

Together with 21453613, 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 (21453613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726805 + 10726806.

It is an arithmetic number, because the mean of its divisors is an integer number (10726806).

Almost surely, 2^21453611 is an apocalyptic number.

21453611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453611 is an equidigital number, since it uses as much as digits as its factorization.

21453611 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 23.

The square root of 21453611 is about 4631.8042920659. The cubic root of 21453611 is about 277.8647574667.

The spelling of 21453611 in words is "twenty-one million, four hundred fifty-three thousand, six hundred eleven".