21450811 has 2 divisors, whose sum is σ = 21450812. Its totient is φ = 21450810.

The previous prime is 21450809. The next prime is 21450827. The reversal of 21450811 is 11805412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21450811 - 2¹ = 21450809 is a prime.

Together with 21450809, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21450211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725405 + 10725406.

It is an arithmetic number, because the mean of its divisors is an integer number (10725406).

Almost surely, 2^21450811 is an apocalyptic number.

21450811 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450811 is an equidigital number, since it uses as much as digits as its factorization.

21450811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21450811 is about 4631.5020241818. The cubic root of 21450811 is about 277.8526685123.

The spelling of 21450811 in words is "twenty-one million, four hundred fifty thousand, eight hundred eleven".