21116253 has 4 divisors (see below), whose sum is σ = 28155008. Its totient is φ = 14077500.

The previous prime is 21116219. The next prime is 21116257. The reversal of 21116253 is 35261112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21116253 - 2¹⁰ = 21115229 is a prime.

It is a super-2 number, since 2×21116253² = 891792281520018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21116257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3519373 + ... + 3519378.

It is an arithmetic number, because the mean of its divisors is an integer number (7038752).

Almost surely, 2^21116253 is an apocalyptic number.

It is an amenable number.

21116253 is a deficient number, since it is larger than the sum of its proper divisors (7038755).

21116253 is an equidigital number, since it uses as much as digits as its factorization.

21116253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7038754.

The product of its digits is 360, while the sum is 21.

The square root of 21116253 is about 4595.2424310367. The cubic root of 21116253 is about 276.4005814181.

Adding to 21116253 its reverse (35261112), we get a palindrome (56377365).

The spelling of 21116253 in words is "twenty-one million, one hundred sixteen thousand, two hundred fifty-three".