21151133 has 4 divisors (see below), whose sum is σ = 21164220. Its totient is φ = 21138048.

The previous prime is 21151069. The next prime is 21151147. The reversal of 21151133 is 33115112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7409284 + 13741849 = 2722^2 + 3707^2 .

It is a cyclic number.

It is not a de Polignac number, because 21151133 - 2⁶ = 21151069 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 (21151183) 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, 3710 + ... + 7487.

It is an arithmetic number, because the mean of its divisors is an integer number (5291055).

Almost surely, 2^21151133 is an apocalyptic number.

It is an amenable number.

21151133 is a deficient number, since it is larger than the sum of its proper divisors (13087).

21151133 is a wasteful number, since it uses less digits than its factorization.

21151133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13086.

The product of its digits is 90, while the sum is 17.

The square root of 21151133 is about 4599.0360946616. The cubic root of 21151133 is about 276.5526846166.

Adding to 21151133 its reverse (33115112), we get a palindrome (54266245).

The spelling of 21151133 in words is "twenty-one million, one hundred fifty-one thousand, one hundred thirty-three".