1291209061 has 2 divisors, whose sum is σ = 1291209062. Its totient is φ = 1291209060.

The previous prime is 1291209037. The next prime is 1291209067. The reversal of 1291209061 is 1609021921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 732784900 + 558424161 = 27070^2 + 23631^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291209061 - 2⁹ = 1291208549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291209067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645604530 + 645604531.

It is an arithmetic number, because the mean of its divisors is an integer number (645604531).

Almost surely, 2^1291209061 is an apocalyptic number.

It is an amenable number.

1291209061 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291209061 is an equidigital number, since it uses as much as digits as its factorization.

1291209061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 1291209061 is about 35933.3975710619. The cubic root of 1291209061 is about 1088.9272224419.

The spelling of 1291209061 in words is "one billion, two hundred ninety-one million, two hundred nine thousand, sixty-one".