21033541 has 2 divisors, whose sum is σ = 21033542. Its totient is φ = 21033540.

The previous prime is 21033521. The next prime is 21033557. The reversal of 21033541 is 14533012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12744900 + 8288641 = 3570^2 + 2879^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033541 - 2⁷ = 21033413 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21033521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516770 + 10516771.

It is an arithmetic number, because the mean of its divisors is an integer number (10516771).

Almost surely, 2^21033541 is an apocalyptic number.

It is an amenable number.

21033541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033541 is an equidigital number, since it uses as much as digits as its factorization.

21033541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21033541 is about 4586.2338579710. The cubic root of 21033541 is about 276.0392237540.

Adding to 21033541 its reverse (14533012), we get a palindrome (35566553).

The spelling of 21033541 in words is "twenty-one million, thirty-three thousand, five hundred forty-one".