1261488643 has 2 divisors, whose sum is σ = 1261488644. Its totient is φ = 1261488642.

The previous prime is 1261488637. The next prime is 1261488647. The reversal of 1261488643 is 3468841621.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261488643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261488643.

It is not a weakly prime, because it can be changed into another prime (1261488647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630744321 + 630744322.

It is an arithmetic number, because the mean of its divisors is an integer number (630744322).

Almost surely, 2^1261488643 is an apocalyptic number.

1261488643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261488643 is an equidigital number, since it uses as much as digits as its factorization.

1261488643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 221184, while the sum is 43.

The square root of 1261488643 is about 35517.4413915192. The cubic root of 1261488643 is about 1080.5074898321.

The spelling of 1261488643 in words is "one billion, two hundred sixty-one million, four hundred eighty-eight thousand, six hundred forty-three".