21423533 has 2 divisors, whose sum is σ = 21423534. Its totient is φ = 21423532.

The previous prime is 21423527. The next prime is 21423539. The reversal of 21423533 is 33532412.

It is a balanced prime because it is at equal distance from previous prime (21423527) and next prime (21423539).

It can be written as a sum of positive squares in only one way, i.e., 12411529 + 9012004 = 3523^2 + 3002^2 .

It is a cyclic number.

It is not a de Polignac number, because 21423533 - 2¹⁶ = 21357997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21423499 and 21423508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711766 + 10711767.

It is an arithmetic number, because the mean of its divisors is an integer number (10711767).

Almost surely, 2^21423533 is an apocalyptic number.

It is an amenable number.

21423533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423533 is an equidigital number, since it uses as much as digits as its factorization.

21423533 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 23.

The square root of 21423533 is about 4628.5562543843. The cubic root of 21423533 is about 277.7348411087.

Adding to 21423533 its reverse (33532412), we get a palindrome (54955945).

The spelling of 21423533 in words is "twenty-one million, four hundred twenty-three thousand, five hundred thirty-three".