21349253 has 4 divisors (see below), whose sum is σ = 21388140. Its totient is φ = 21310368.

The previous prime is 21349243. The next prime is 21349277. The reversal of 21349253 is 35294312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5484964 + 15864289 = 2342^2 + 3983^2 .

It is a cyclic number.

It is not a de Polignac number, because 21349253 - 2⁶ = 21349189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21349213) 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 in 3 ways as a sum of consecutive naturals, for example, 18608 + ... + 19721.

It is an arithmetic number, because the mean of its divisors is an integer number (5347035).

Almost surely, 2^21349253 is an apocalyptic number.

It is an amenable number.

21349253 is a deficient number, since it is larger than the sum of its proper divisors (38887).

21349253 is an equidigital number, since it uses as much as digits as its factorization.

21349253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38886.

The product of its digits is 6480, while the sum is 29.

The square root of 21349253 is about 4620.5251865995. The cubic root of 21349253 is about 277.4134805893.

The spelling of 21349253 in words is "twenty-one million, three hundred forty-nine thousand, two hundred fifty-three".