1291536881 has 2 divisors, whose sum is σ = 1291536882. Its totient is φ = 1291536880.

The previous prime is 1291536877. The next prime is 1291536899. The reversal of 1291536881 is 1886351921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1215568225 + 75968656 = 34865^2 + 8716^2 .

It is an emirp because it is prime and its reverse (1886351921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291536881 - 2² = 1291536877 is a prime.

It is a super-2 number, since 2×1291536881² = 3336135029966416322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1291536821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645768440 + 645768441.

It is an arithmetic number, because the mean of its divisors is an integer number (645768441).

Almost surely, 2^1291536881 is an apocalyptic number.

It is an amenable number.

1291536881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291536881 is an equidigital number, since it uses as much as digits as its factorization.

1291536881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680, while the sum is 44.

The square root of 1291536881 is about 35937.9587762021. The cubic root of 1291536881 is about 1089.0193691301.

The spelling of 1291536881 in words is "one billion, two hundred ninety-one million, five hundred thirty-six thousand, eight hundred eighty-one".