1091261881 has 2 divisors, whose sum is σ = 1091261882. Its totient is φ = 1091261880.

The previous prime is 1091261849. The next prime is 1091261917. The reversal of 1091261881 is 1881621901.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 747530281 + 343731600 = 27341^2 + 18540^2 .

It is an emirp because it is prime and its reverse (1881621901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1091261881 - 2⁵ = 1091261849 is a prime.

It is a super-2 number, since 2×1091261881² = 2381704985847316322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1091261881.

It is not a weakly prime, because it can be changed into another prime (1091268881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545630940 + 545630941.

It is an arithmetic number, because the mean of its divisors is an integer number (545630941).

Almost surely, 2^1091261881 is an apocalyptic number.

It is an amenable number.

1091261881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091261881 is an equidigital number, since it uses as much as digits as its factorization.

1091261881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 37.

The square root of 1091261881 is about 33034.2531473015. The cubic root of 1091261881 is about 1029.5394557154.

The spelling of 1091261881 in words is "one billion, ninety-one million, two hundred sixty-one thousand, eight hundred eighty-one".