21290933 has 2 divisors, whose sum is σ = 21290934. Its totient is φ = 21290932.

The previous prime is 21290923. The next prime is 21290999. The reversal of 21290933 is 33909212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10903204 + 10387729 = 3302^2 + 3223^2 .

It is a cyclic number.

It is not a de Polignac number, because 21290933 - 2¹⁴ = 21274549 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21290896 and 21290905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21290903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10645466 + 10645467.

It is an arithmetic number, because the mean of its divisors is an integer number (10645467).

Almost surely, 2^21290933 is an apocalyptic number.

It is an amenable number.

21290933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21290933 is an equidigital number, since it uses as much as digits as its factorization.

21290933 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 21290933 is about 4614.2098998637. The cubic root of 21290933 is about 277.1606456933.

The spelling of 21290933 in words is "twenty-one million, two hundred ninety thousand, nine hundred thirty-three".