1261672609 has 2 divisors, whose sum is σ = 1261672610. Its totient is φ = 1261672608.

The previous prime is 1261672603. The next prime is 1261672619. The reversal of 1261672609 is 9062761621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1261670400 + 2209 = 35520^2 + 47^2 .

It is an emirp because it is prime and its reverse (9062761621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261672609 - 2⁷ = 1261672481 is a prime.

It is not a weakly prime, because it can be changed into another prime (1261672603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630836304 + 630836305.

It is an arithmetic number, because the mean of its divisors is an integer number (630836305).

Almost surely, 2^1261672609 is an apocalyptic number.

It is an amenable number.

1261672609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261672609 is an equidigital number, since it uses as much as digits as its factorization.

1261672609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 1261672609 is about 35520.0310951440. The cubic root of 1261672609 is about 1080.5600116364.

The spelling of 1261672609 in words is "one billion, two hundred sixty-one million, six hundred seventy-two thousand, six hundred nine".