21423535 has 12 divisors (see below), whose sum is σ = 29905848. Its totient is φ = 14690256.

The previous prime is 21423533. The next prime is 21423539. The reversal of 21423535 is 53532412.

It is not a de Polignac number, because 21423535 - 2¹ = 21423533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423533) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43477 + ... + 43966.

It is an arithmetic number, because the mean of its divisors is an integer number (2492154).

Almost surely, 2^21423535 is an apocalyptic number.

21423535 is a deficient number, since it is larger than the sum of its proper divisors (8482313).

21423535 is an equidigital number, since it uses as much as digits as its factorization.

21423535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87462 (or 87455 counting only the distinct ones).

The product of its digits is 3600, while the sum is 25.

The square root of 21423535 is about 4628.5564704344. The cubic root of 21423535 is about 277.7348497514.

Adding to 21423535 its reverse (53532412), we get a palindrome (74955947).

The spelling of 21423535 in words is "twenty-one million, four hundred twenty-three thousand, five hundred thirty-five".