21272663 has 4 divisors (see below), whose sum is σ = 21674088. Its totient is φ = 20871240.

The previous prime is 21272621. The next prime is 21272681. The reversal of 21272663 is 36627212.

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

It is a cyclic number.

It is not a de Polignac number, because 21272663 - 2¹² = 21268567 is a prime.

It is a super-2 number, since 2×21272663² = 905052382223138, 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 (21272683) 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, 200633 + ... + 200738.

It is an arithmetic number, because the mean of its divisors is an integer number (5418522).

Almost surely, 2^21272663 is an apocalyptic number.

21272663 is a deficient number, since it is larger than the sum of its proper divisors (401425).

21272663 is an equidigital number, since it uses as much as digits as its factorization.

21272663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401424.

The product of its digits is 6048, while the sum is 29.

The square root of 21272663 is about 4612.2297210785. The cubic root of 21272663 is about 277.0813447361.

Adding to 21272663 its reverse (36627212), we get a palindrome (57899875).

The spelling of 21272663 in words is "twenty-one million, two hundred seventy-two thousand, six hundred sixty-three".