1261611133 has 2 divisors, whose sum is σ = 1261611134. Its totient is φ = 1261611132.

The previous prime is 1261611103. The next prime is 1261611167. The reversal of 1261611133 is 3311161621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 789722404 + 471888729 = 28102^2 + 21723^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261611133 - 2²⁵ = 1228056701 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1261611098 and 1261611107.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261611103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630805566 + 630805567.

It is an arithmetic number, because the mean of its divisors is an integer number (630805567).

Almost surely, 2^1261611133 is an apocalyptic number.

It is an amenable number.

1261611133 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261611133 is an equidigital number, since it uses as much as digits as its factorization.

1261611133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 1261611133 is about 35519.1657137383. The cubic root of 1261611133 is about 1080.5424609697.

Adding to 1261611133 its reverse (3311161621), we get a palindrome (4572772754).

The spelling of 1261611133 in words is "one billion, two hundred sixty-one million, six hundred eleven thousand, one hundred thirty-three".