21116633 has 2 divisors, whose sum is σ = 21116634. Its totient is φ = 21116632.

The previous prime is 21116629. The next prime is 21116639. The reversal of 21116633 is 33661112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20912329 + 204304 = 4573^2 + 452^2 .

It is a cyclic number.

It is not a de Polignac number, because 21116633 - 2² = 21116629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21116599 and 21116608.

It is not a weakly prime, because it can be changed into another prime (21116639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558316 + 10558317.

It is an arithmetic number, because the mean of its divisors is an integer number (10558317).

Almost surely, 2^21116633 is an apocalyptic number.

It is an amenable number.

21116633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116633 is an equidigital number, since it uses as much as digits as its factorization.

21116633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 23.

The square root of 21116633 is about 4595.2837779619. The cubic root of 21116633 is about 276.4022394078.

Adding to 21116633 its reverse (33661112), we get a palindrome (54777745).

The spelling of 21116633 in words is "twenty-one million, one hundred sixteen thousand, six hundred thirty-three".