21269247 has 4 divisors (see below), whose sum is σ = 28359000. Its totient is φ = 14179496.

The previous prime is 21269243. The next prime is 21269251. The reversal of 21269247 is 74296212.

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

It is an interprime number because it is at equal distance from previous prime (21269243) and next prime (21269251).

It is a cyclic number.

It is not a de Polignac number, because 21269247 - 2² = 21269243 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21269243) 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, 3544872 + ... + 3544877.

It is an arithmetic number, because the mean of its divisors is an integer number (7089750).

Almost surely, 2^21269247 is an apocalyptic number.

21269247 is a deficient number, since it is larger than the sum of its proper divisors (7089753).

21269247 is an equidigital number, since it uses as much as digits as its factorization.

21269247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7089752.

The product of its digits is 12096, while the sum is 33.

The square root of 21269247 is about 4611.8593864080. The cubic root of 21269247 is about 277.0665125460.

The spelling of 21269247 in words is "twenty-one million, two hundred sixty-nine thousand, two hundred forty-seven".