21798653 has 2 divisors, whose sum is σ = 21798654. Its totient is φ = 21798652.

The previous prime is 21798631. The next prime is 21798683. The reversal of 21798653 is 35689712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12201049 + 9597604 = 3493^2 + 3098^2 .

It is a cyclic number.

It is not a de Polignac number, because 21798653 - 2¹² = 21794557 is a prime.

It is a super-2 number, since 2×21798653² = 950362545228818, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21798653.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21798613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10899326 + 10899327.

It is an arithmetic number, because the mean of its divisors is an integer number (10899327).

Almost surely, 2^21798653 is an apocalyptic number.

It is an amenable number.

21798653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21798653 is an equidigital number, since it uses as much as digits as its factorization.

21798653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The square root of 21798653 is about 4668.9027618917. The cubic root of 21798653 is about 279.3464903752.

The spelling of 21798653 in words is "twenty-one million, seven hundred ninety-eight thousand, six hundred fifty-three".