21268253 has 2 divisors, whose sum is σ = 21268254. Its totient is φ = 21268252.

The previous prime is 21268249. The next prime is 21268259. The reversal of 21268253 is 35286212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20994724 + 273529 = 4582^2 + 523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21268253 - 2² = 21268249 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21268259) 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, 10634126 + 10634127.

It is an arithmetic number, because the mean of its divisors is an integer number (10634127).

Almost surely, 2^21268253 is an apocalyptic number.

It is an amenable number.

21268253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21268253 is an equidigital number, since it uses as much as digits as its factorization.

21268253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 29.

The square root of 21268253 is about 4611.7516195042. The cubic root of 21268253 is about 277.0621963236.

The spelling of 21268253 in words is "twenty-one million, two hundred sixty-eight thousand, two hundred fifty-three".