1261371149 has 4 divisors (see below), whose sum is σ = 1263588540. Its totient is φ = 1259153760.

The previous prime is 1261371091. The next prime is 1261371157. The reversal of 1261371149 is 9411731621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9411731621 = 127 ⋅74108123.

It can be written as a sum of positive squares in 2 ways, for example, as 187498249 + 1073872900 = 13693^2 + 32770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261371149 - 2¹² = 1261367053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261571149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1107842 + ... + 1108979.

It is an arithmetic number, because the mean of its divisors is an integer number (315897135).

Almost surely, 2^1261371149 is an apocalyptic number.

It is an amenable number.

1261371149 is a deficient number, since it is larger than the sum of its proper divisors (2217391).

1261371149 is an equidigital number, since it uses as much as digits as its factorization.

1261371149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2217390.

The product of its digits is 9072, while the sum is 35.

The square root of 1261371149 is about 35515.7873205706. The cubic root of 1261371149 is about 1080.4739429351.

The spelling of 1261371149 in words is "one billion, two hundred sixty-one million, three hundred seventy-one thousand, one hundred forty-nine".