21012133 has 4 divisors (see below), whose sum is σ = 21925728. Its totient is φ = 20098540.

The previous prime is 21012127. The next prime is 21012137. The reversal of 21012133 is 33121012.

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 21012133 - 2⁹ = 21011621 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 (21012137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 456763 + ... + 456808.

It is an arithmetic number, because the mean of its divisors is an integer number (5481432).

Almost surely, 2^21012133 is an apocalyptic number.

21012133 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21012133 is a deficient number, since it is larger than the sum of its proper divisors (913595).

21012133 is an equidigital number, since it uses as much as digits as its factorization.

21012133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913594.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21012133 is about 4583.8993226292. The cubic root of 21012133 is about 275.9455407848.

Adding to 21012133 its reverse (33121012), we get a palindrome (54133145).

The spelling of 21012133 in words is "twenty-one million, twelve thousand, one hundred thirty-three".