21433663 has 4 divisors (see below), whose sum is σ = 21602560. Its totient is φ = 21264768.

The previous prime is 21433649. The next prime is 21433667. The reversal of 21433663 is 36633412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21433663 - 2⁹ = 21433151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21433667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84258 + ... + 84511.

It is an arithmetic number, because the mean of its divisors is an integer number (5400640).

Almost surely, 2^21433663 is an apocalyptic number.

21433663 is a deficient number, since it is larger than the sum of its proper divisors (168897).

21433663 is a wasteful number, since it uses less digits than its factorization.

21433663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168896.

The product of its digits is 7776, while the sum is 28.

The square root of 21433663 is about 4629.6504187681. The cubic root of 21433663 is about 277.7786093427.

The spelling of 21433663 in words is "twenty-one million, four hundred thirty-three thousand, six hundred sixty-three".