21021127 has 2 divisors, whose sum is σ = 21021128. Its totient is φ = 21021126.

The previous prime is 21021107. The next prime is 21021157. The reversal of 21021127 is 72112012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021127 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21021127.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510563 + 10510564.

It is an arithmetic number, because the mean of its divisors is an integer number (10510564).

Almost surely, 2^21021127 is an apocalyptic number.

21021127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021127 is an equidigital number, since it uses as much as digits as its factorization.

21021127 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21021127 is about 4584.8802601595. The cubic root of 21021127 is about 275.9849069321.

Adding to 21021127 its reverse (72112012), we get a palindrome (93133139).

The spelling of 21021127 in words is "twenty-one million, twenty-one thousand, one hundred twenty-seven".