21727247 has 2 divisors, whose sum is σ = 21727248. Its totient is φ = 21727246.

The previous prime is 21727231. The next prime is 21727271. The reversal of 21727247 is 74272712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21727247 - 2⁴ = 21727231 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21727217) 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 as a sum of consecutive naturals, namely, 10863623 + 10863624.

It is an arithmetic number, because the mean of its divisors is an integer number (10863624).

Almost surely, 2^21727247 is an apocalyptic number.

21727247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21727247 is an equidigital number, since it uses as much as digits as its factorization.

21727247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10976, while the sum is 32.

The square root of 21727247 is about 4661.2495105926. The cubic root of 21727247 is about 279.0411376330.

Adding to 21727247 its reverse (74272712), we get a palindrome (95999959).

The spelling of 21727247 in words is "twenty-one million, seven hundred twenty-seven thousand, two hundred forty-seven".