1261645457 has 2 divisors, whose sum is σ = 1261645458. Its totient is φ = 1261645456.

The previous prime is 1261645423. The next prime is 1261645513. The reversal of 1261645457 is 7545461621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1129027201 + 132618256 = 33601^2 + 11516^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261645457 - 2¹² = 1261641361 is a prime.

It is not a weakly prime, because it can be changed into another prime (1261645417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630822728 + 630822729.

It is an arithmetic number, because the mean of its divisors is an integer number (630822729).

Almost surely, 2^1261645457 is an apocalyptic number.

It is an amenable number.

1261645457 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261645457 is an equidigital number, since it uses as much as digits as its factorization.

1261645457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 41.

The square root of 1261645457 is about 35519.6488862151. The cubic root of 1261645457 is about 1080.5522601337.

The spelling of 1261645457 in words is "one billion, two hundred sixty-one million, six hundred forty-five thousand, four hundred fifty-seven".