21905053 has 2 divisors, whose sum is σ = 21905054. Its totient is φ = 21905052.

The previous prime is 21905011. The next prime is 21905071. The reversal of 21905053 is 35050912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15155449 + 6749604 = 3893^2 + 2598^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21905053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21905083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10952526 + 10952527.

It is an arithmetic number, because the mean of its divisors is an integer number (10952527).

Almost surely, 2^21905053 is an apocalyptic number.

It is an amenable number.

21905053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21905053 is an equidigital number, since it uses as much as digits as its factorization.

21905053 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1350, while the sum is 25.

The square root of 21905053 is about 4680.2834315883. The cubic root of 21905053 is about 279.8002529460.

Adding to 21905053 its reverse (35050912), we get a palindrome (56955965).

The spelling of 21905053 in words is "twenty-one million, nine hundred five thousand, fifty-three".