21580271 has 2 divisors, whose sum is σ = 21580272. Its totient is φ = 21580270.

The previous prime is 21580267. The next prime is 21580283. The reversal of 21580271 is 17208512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21580271 - 2² = 21580267 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21580271.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21580201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10790135 + 10790136.

It is an arithmetic number, because the mean of its divisors is an integer number (10790136).

Almost surely, 2^21580271 is an apocalyptic number.

21580271 is a deficient number, since it is larger than the sum of its proper divisors (1).

21580271 is an equidigital number, since it uses as much as digits as its factorization.

21580271 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21580271 is about 4645.4570281082. The cubic root of 21580271 is about 278.4105135345.

Adding to 21580271 its reverse (17208512), we get a palindrome (38788783).

The spelling of 21580271 in words is "twenty-one million, five hundred eighty thousand, two hundred seventy-one".