21272647 has 18 divisors (see below), whose sum is σ = 24728424. Its totient is φ = 18283320.

The previous prime is 21272621. The next prime is 21272681. The reversal of 21272647 is 74627212.

It is a de Polignac number, because none of the positive numbers 2^k-21272647 is a prime.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21272617) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 43438 + ... + 43924.

Almost surely, 2^21272647 is an apocalyptic number.

21272647 is a deficient number, since it is larger than the sum of its proper divisors (3455777).

21272647 is a wasteful number, since it uses less digits than its factorization.

21272647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547 (or 517 counting only the distinct ones).

The product of its digits is 9408, while the sum is 31.

The square root of 21272647 is about 4612.2279865592. The cubic root of 21272647 is about 277.0812752682.

Adding to 21272647 its reverse (74627212), we get a palindrome (95899859).

It can be divided in two parts, 2127 and 2647, that added together give a palindrome (4774).

The spelling of 21272647 in words is "twenty-one million, two hundred seventy-two thousand, six hundred forty-seven".