21833993 has 4 divisors (see below), whose sum is σ = 21844608. Its totient is φ = 21823380.

The previous prime is 21833963. The next prime is 21834011. The reversal of 21833993 is 39933812.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21833993 - 2¹² = 21829897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21833963) 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, 1121 + ... + 6702.

It is an arithmetic number, because the mean of its divisors is an integer number (5461152).

Almost surely, 2^21833993 is an apocalyptic number.

It is an amenable number.

21833993 is a deficient number, since it is larger than the sum of its proper divisors (10615).

21833993 is an equidigital number, since it uses as much as digits as its factorization.

21833993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10614.

The product of its digits is 34992, while the sum is 38.

The square root of 21833993 is about 4672.6858443512. The cubic root of 21833993 is about 279.4973678152.

It can be divided in two parts, 2 and 1833993, that multiplied together give a triangular number (3667986 = T₂₇₀₈).

The spelling of 21833993 in words is "twenty-one million, eight hundred thirty-three thousand, nine hundred ninety-three".