21068653 has 2 divisors, whose sum is σ = 21068654. Its totient is φ = 21068652.

The previous prime is 21068617. The next prime is 21068657. The reversal of 21068653 is 35686012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10745284 + 10323369 = 3278^2 + 3213^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21068653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21068657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10534326 + 10534327.

It is an arithmetic number, because the mean of its divisors is an integer number (10534327).

Almost surely, 2^21068653 is an apocalyptic number.

It is an amenable number.

21068653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21068653 is an equidigital number, since it uses as much as digits as its factorization.

21068653 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 21068653 is about 4590.0602392561. The cubic root of 21068653 is about 276.1927388944.

The spelling of 21068653 in words is "twenty-one million, sixty-eight thousand, six hundred fifty-three".