1271258437681 has 4 divisors (see below), whose sum is σ = 1271554841700. Its totient is φ = 1270962033664.

The previous prime is 1271258437667. The next prime is 1271258437699. The reversal of 1271258437681 is 1867348521721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 589616658225 + 681641779456 = 767865^2 + 825616^2 .

It is a cyclic number.

It is not a de Polignac number, because 1271258437681 - 2¹⁷ = 1271258306609 is a prime.

It is a super-2 number, since 2×1271258437681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1271258437381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148195576 + ... + 148204153.

It is an arithmetic number, because the mean of its divisors is an integer number (317888710425).

Almost surely, 2^{1271258437681} is an apocalyptic number.

It is an amenable number.

1271258437681 is a deficient number, since it is larger than the sum of its proper divisors (296404019).

1271258437681 is an equidigital number, since it uses as much as digits as its factorization.

1271258437681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296404018.

The product of its digits is 4515840, while the sum is 55.

The spelling of 1271258437681 in words is "one trillion, two hundred seventy-one billion, two hundred fifty-eight million, four hundred thirty-seven thousand, six hundred eighty-one".