21253033 has 2 divisors, whose sum is σ = 21253034. Its totient is φ = 21253032.

The previous prime is 21253021. The next prime is 21253093. The reversal of 21253033 is 33035212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16621929 + 4631104 = 4077^2 + 2152^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21253033 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21253033.

It is not a weakly prime, because it can be changed into another prime (21253093) 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, 10626516 + 10626517.

It is an arithmetic number, because the mean of its divisors is an integer number (10626517).

Almost surely, 2^21253033 is an apocalyptic number.

It is an amenable number.

21253033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253033 is an equidigital number, since it uses as much as digits as its factorization.

21253033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 19.

The square root of 21253033 is about 4610.1011919480. The cubic root of 21253033 is about 276.9960900802.

Adding to 21253033 its reverse (33035212), we get a palindrome (54288245).

The spelling of 21253033 in words is "twenty-one million, two hundred fifty-three thousand, thirty-three".