21123033 has 4 divisors (see below), whose sum is σ = 28164048. Its totient is φ = 14082020.

The previous prime is 21123029. The next prime is 21123043. The reversal of 21123033 is 33032112.

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.

It is a cyclic number.

It is not a de Polignac number, because 21123033 - 2² = 21123029 is a prime.

It is a super-3 number, since 3×21123033³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21123013) 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 3 ways as a sum of consecutive naturals, for example, 3520503 + ... + 3520508.

It is an arithmetic number, because the mean of its divisors is an integer number (7041012).

Almost surely, 2^21123033 is an apocalyptic number.

It is an amenable number.

21123033 is a deficient number, since it is larger than the sum of its proper divisors (7041015).

21123033 is an equidigital number, since it uses as much as digits as its factorization.

21123033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041014.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21123033 is about 4595.9800913407. The cubic root of 21123033 is about 276.4301604570.

Adding to 21123033 its reverse (33032112), we get a palindrome (54155145).

The spelling of 21123033 in words is "twenty-one million, one hundred twenty-three thousand, thirty-three".