21909383 has 4 divisors (see below), whose sum is σ = 21928440. Its totient is φ = 21890328.

The previous prime is 21909373. The next prime is 21909389. The reversal of 21909383 is 38390912.

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 21909383 - 2¹² = 21905287 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 (21909389) 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, 7685 + ... + 10142.

It is an arithmetic number, because the mean of its divisors is an integer number (5482110).

Almost surely, 2^21909383 is an apocalyptic number.

21909383 is a deficient number, since it is larger than the sum of its proper divisors (19057).

21909383 is a wasteful number, since it uses less digits than its factorization.

21909383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19056.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 21909383 is about 4680.7459875537. The cubic root of 21909383 is about 279.8186878900.

The spelling of 21909383 in words is "twenty-one million, nine hundred nine thousand, three hundred eighty-three".