21266533 has 4 divisors (see below), whose sum is σ = 21373600. Its totient is φ = 21159468.

The previous prime is 21266521. The next prime is 21266551. The reversal of 21266533 is 33566212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21266533 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 (21266503) 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, 53235 + ... + 53632.

It is an arithmetic number, because the mean of its divisors is an integer number (5343400).

Almost surely, 2^21266533 is an apocalyptic number.

It is an amenable number.

21266533 is a deficient number, since it is larger than the sum of its proper divisors (107067).

21266533 is a wasteful number, since it uses less digits than its factorization.

21266533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107066.

The product of its digits is 6480, while the sum is 28.

The square root of 21266533 is about 4611.5651356129. The cubic root of 21266533 is about 277.0547272910.

The spelling of 21266533 in words is "twenty-one million, two hundred sixty-six thousand, five hundred thirty-three".