21745127 has 2 divisors, whose sum is σ = 21745128. Its totient is φ = 21745126.

The previous prime is 21745123. The next prime is 21745133. The reversal of 21745127 is 72154712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21745127 - 2² = 21745123 is a prime.

It is a super-2 number, since 2×21745127² = 945701096492258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21745127.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21745121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10872563 + 10872564.

It is an arithmetic number, because the mean of its divisors is an integer number (10872564).

Almost surely, 2^21745127 is an apocalyptic number.

21745127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21745127 is an equidigital number, since it uses as much as digits as its factorization.

21745127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3920, while the sum is 29.

The square root of 21745127 is about 4663.1670568402. The cubic root of 21745127 is about 279.1176604059.

Adding to 21745127 its reverse (72154712), we get a palindrome (93899839).

The spelling of 21745127 in words is "twenty-one million, seven hundred forty-five thousand, one hundred twenty-seven".