21183391 has 8 divisors (see below), whose sum is σ = 22619520. Its totient is φ = 19790232.

The previous prime is 21183389. The next prime is 21183431. The reversal of 21183391 is 19338112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21183391 - 2¹ = 21183389 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 (21183341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9721 + ... + 11698.

It is an arithmetic number, because the mean of its divisors is an integer number (2827440).

Almost surely, 2^21183391 is an apocalyptic number.

21183391 is a deficient number, since it is larger than the sum of its proper divisors (1436129).

21183391 is a wasteful number, since it uses less digits than its factorization.

21183391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21485.

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

The square root of 21183391 is about 4602.5417977461. The cubic root of 21183391 is about 276.6932051445.

The spelling of 21183391 in words is "twenty-one million, one hundred eighty-three thousand, three hundred ninety-one".