1261457641 has 2 divisors, whose sum is σ = 1261457642. Its totient is φ = 1261457640.

The previous prime is 1261457623. The next prime is 1261457651. The reversal of 1261457641 is 1467541621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 876160000 + 385297641 = 29600^2 + 19629^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261457641 - 2⁷ = 1261457513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261457641.

It is not a weakly prime, because it can be changed into another prime (1261457621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630728820 + 630728821.

It is an arithmetic number, because the mean of its divisors is an integer number (630728821).

Almost surely, 2^1261457641 is an apocalyptic number.

It is an amenable number.

1261457641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261457641 is an equidigital number, since it uses as much as digits as its factorization.

1261457641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 37.

The square root of 1261457641 is about 35517.0049553731. The cubic root of 1261457641 is about 1080.4986383407.

The spelling of 1261457641 in words is "one billion, two hundred sixty-one million, four hundred fifty-seven thousand, six hundred forty-one".