21133493 has 2 divisors, whose sum is σ = 21133494. Its totient is φ = 21133492.

The previous prime is 21133477. The next prime is 21133513. The reversal of 21133493 is 39433112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16459249 + 4674244 = 4057^2 + 2162^2 .

It is a cyclic number.

It is not a de Polignac number, because 21133493 - 2⁴ = 21133477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21133403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10566746 + 10566747.

It is an arithmetic number, because the mean of its divisors is an integer number (10566747).

Almost surely, 2^21133493 is an apocalyptic number.

It is an amenable number.

21133493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21133493 is an equidigital number, since it uses as much as digits as its factorization.

21133493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 26.

The square root of 21133493 is about 4597.1179014683. The cubic root of 21133493 is about 276.4757817832.

The spelling of 21133493 in words is "twenty-one million, one hundred thirty-three thousand, four hundred ninety-three".