21356633 has 2 divisors, whose sum is σ = 21356634. Its totient is φ = 21356632.

The previous prime is 21356611. The next prime is 21356653. The reversal of 21356633 is 33665312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11888704 + 9467929 = 3448^2 + 3077^2 .

It is a cyclic number.

It is not a de Polignac number, because 21356633 - 2¹⁶ = 21291097 is a prime.

It is a super-2 number, since 2×21356633² = 912211546193378, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21356596 and 21356605.

It is not a weakly prime, because it can be changed into another prime (21356603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678316 + 10678317.

It is an arithmetic number, because the mean of its divisors is an integer number (10678317).

Almost surely, 2^21356633 is an apocalyptic number.

It is an amenable number.

21356633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21356633 is an equidigital number, since it uses as much as digits as its factorization.

21356633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 29.

The square root of 21356633 is about 4621.3237281108. The cubic root of 21356633 is about 277.4454422950.

The spelling of 21356633 in words is "twenty-one million, three hundred fifty-six thousand, six hundred thirty-three".