21272553 has 6 divisors (see below), whose sum is σ = 30727034. Its totient is φ = 14181696.

The previous prime is 21272527. The next prime is 21272561. The reversal of 21272553 is 35527212.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 451584 = 4563^2 + 672^2 .

It is not a de Polignac number, because 21272553 - 2⁸ = 21272297 is a prime.

It is a super-2 number, since 2×21272553² = 905043022275618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21272453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1181800 + ... + 1181817.

Almost surely, 2^21272553 is an apocalyptic number.

It is an amenable number.

21272553 is a deficient number, since it is larger than the sum of its proper divisors (9454481).

21272553 is a wasteful number, since it uses less digits than its factorization.

21272553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363623 (or 2363620 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 21272553 is about 4612.2177962451. The cubic root of 21272553 is about 277.0808671435.

Adding to 21272553 its reverse (35527212), we get a palindrome (56799765).

The spelling of 21272553 in words is "twenty-one million, two hundred seventy-two thousand, five hundred fifty-three".