21033399 has 8 divisors (see below), whose sum is σ = 29520640. Its totient is φ = 13284216.

The previous prime is 21033391. The next prime is 21033401. The reversal of 21033399 is 99333012.

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

It is not a de Polignac number, because 21033399 - 2³ = 21033391 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 (21033391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 184447 + ... + 184560.

It is an arithmetic number, because the mean of its divisors is an integer number (3690080).

Almost surely, 2^21033399 is an apocalyptic number.

21033399 is a deficient number, since it is larger than the sum of its proper divisors (8487241).

21033399 is a wasteful number, since it uses less digits than its factorization.

21033399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369029.

The product of its (nonzero) digits is 4374, while the sum is 30.

The square root of 21033399 is about 4586.2183768329. The cubic root of 21033399 is about 276.0386025611.

The spelling of 21033399 in words is "twenty-one million, thirty-three thousand, three hundred ninety-nine".