21933811 has 4 divisors (see below), whose sum is σ = 22468824. Its totient is φ = 21398800.

The previous prime is 21933787. The next prime is 21933839. The reversal of 21933811 is 11833912.

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 21933811 - 2⁷ = 21933683 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21933811.

It is not an unprimeable number, because it can be changed into a prime (21933851) 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, 267445 + ... + 267526.

It is an arithmetic number, because the mean of its divisors is an integer number (5617206).

Almost surely, 2^21933811 is an apocalyptic number.

21933811 is a deficient number, since it is larger than the sum of its proper divisors (535013).

21933811 is an equidigital number, since it uses as much as digits as its factorization.

21933811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535012.

The product of its digits is 1296, while the sum is 28.

The square root of 21933811 is about 4683.3546737355. The cubic root of 21933811 is about 279.9226444473.

The spelling of 21933811 in words is "twenty-one million, nine hundred thirty-three thousand, eight hundred eleven".