21158633 has 2 divisors, whose sum is σ = 21158634. Its totient is φ = 21158632.

The previous prime is 21158563. The next prime is 21158671. The reversal of 21158633 is 33685112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14645929 + 6512704 = 3827^2 + 2552^2 .

It is a cyclic number.

It is not a de Polignac number, because 21158633 - 2⁸ = 21158377 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21158596 and 21158605.

It is not a weakly prime, because it can be changed into another prime (21158933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579316 + 10579317.

It is an arithmetic number, because the mean of its divisors is an integer number (10579317).

Almost surely, 2^21158633 is an apocalyptic number.

It is an amenable number.

21158633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21158633 is an equidigital number, since it uses as much as digits as its factorization.

21158633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 29.

The square root of 21158633 is about 4599.8514106436. The cubic root of 21158633 is about 276.5853684453.

The spelling of 21158633 in words is "twenty-one million, one hundred fifty-eight thousand, six hundred thirty-three".