21271277 has 2 divisors, whose sum is σ = 21271278. Its totient is φ = 21271276.

The previous prime is 21271259. The next prime is 21271319. The reversal of 21271277 is 77217212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12187081 + 9084196 = 3491^2 + 3014^2 .

It is a cyclic number.

It is not a de Polignac number, because 21271277 - 2²² = 17076973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21271207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10635638 + 10635639.

It is an arithmetic number, because the mean of its divisors is an integer number (10635639).

Almost surely, 2^21271277 is an apocalyptic number.

It is an amenable number.

21271277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21271277 is an equidigital number, since it uses as much as digits as its factorization.

21271277 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2744, while the sum is 29.

The square root of 21271277 is about 4612.0794659242. The cubic root of 21271277 is about 277.0753269488.

Adding to 21271277 its reverse (77217212), we get a palindrome (98488489).

The spelling of 21271277 in words is "twenty-one million, two hundred seventy-one thousand, two hundred seventy-seven".