1271289521 has 2 divisors, whose sum is σ = 1271289522. Its totient is φ = 1271289520.

The previous prime is 1271289499. The next prime is 1271289541. The reversal of 1271289521 is 1259821721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1255993600 + 15295921 = 35440^2 + 3911^2 .

It is a cyclic number.

It is not a de Polignac number, because 1271289521 - 2¹⁸ = 1271027377 is a prime.

It is not a weakly prime, because it can be changed into another prime (1271289541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 635644760 + 635644761.

It is an arithmetic number, because the mean of its divisors is an integer number (635644761).

Almost surely, 2^1271289521 is an apocalyptic number.

It is an amenable number.

1271289521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1271289521 is an equidigital number, since it uses as much as digits as its factorization.

1271289521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 38.

The square root of 1271289521 is about 35655.1471880288. The cubic root of 1271289521 is about 1083.2985347612.

The spelling of 1271289521 in words is "one billion, two hundred seventy-one million, two hundred eighty-nine thousand, five hundred twenty-one".