1261649 has 2 divisors, whose sum is σ = 1261650. Its totient is φ = 1261648.

The previous prime is 1261643. The next prime is 1261697. The reversal of 1261649 is 9461621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1117249 + 144400 = 1057^2 + 380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1261643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630824 + 630825.

It is an arithmetic number, because the mean of its divisors is an integer number (630825).

2^1261649 is an apocalyptic number.

It is an amenable number.

1261649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261649 is an equidigital number, since it uses as much as digits as its factorization.

1261649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 1261649 is about 1123.2314988461. The cubic root of 1261649 is about 108.0553271615.

The spelling of 1261649 in words is "one million, two hundred sixty-one thousand, six hundred forty-nine".