21042053 has 2 divisors, whose sum is σ = 21042054. Its totient is φ = 21042052.

The previous prime is 21042017. The next prime is 21042059. The reversal of 21042053 is 35024012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18679684 + 2362369 = 4322^2 + 1537^2 .

It is a cyclic number.

It is not a de Polignac number, because 21042053 - 2⁶ = 21041989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21042059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521026 + 10521027.

It is an arithmetic number, because the mean of its divisors is an integer number (10521027).

Almost surely, 2^21042053 is an apocalyptic number.

It is an amenable number.

21042053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21042053 is an equidigital number, since it uses as much as digits as its factorization.

21042053 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21042053 is about 4587.1617586477. The cubic root of 21042053 is about 276.0764552246.

Adding to 21042053 its reverse (35024012), we get a palindrome (56066065).

The spelling of 21042053 in words is "twenty-one million, forty-two thousand, fifty-three".