21301823 has 2 divisors, whose sum is σ = 21301824. Its totient is φ = 21301822.

The previous prime is 21301801. The next prime is 21301843. The reversal of 21301823 is 32810312.

It is an a-pointer prime, because the next prime (21301843) can be obtained adding 21301823 to its sum of digits (20).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21301823 - 2⁶ = 21301759 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21301795 and 21301804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21301843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650911 + 10650912.

It is an arithmetic number, because the mean of its divisors is an integer number (10650912).

Almost surely, 2^21301823 is an apocalyptic number.

21301823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21301823 is an equidigital number, since it uses as much as digits as its factorization.

21301823 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21301823 is about 4615.3897993561. The cubic root of 21301823 is about 277.2078921742.

The spelling of 21301823 in words is "twenty-one million, three hundred one thousand, eight hundred twenty-three".