1263215561 has 2 divisors, whose sum is σ = 1263215562.
Its totient is φ = 1263215560.
The previous prime is 1263215543. The next prime is 1263215573. The reversal of 1263215561 is 1655123621.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1120173961 + 143041600 = 33469^2 + 11960^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-1263215561 is a prime.
It is not a weakly prime, because it can be changed into another prime (1263215531) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631607780 + 631607781.
It is an arithmetic number, because the mean of its divisors is an integer number (631607781).
Almost surely, 21263215561 is an apocalyptic number.
It is an amenable number.
1263215561 is a deficient number, since it is larger than the sum of its proper divisors (1).
1263215561 is an equidigital number, since it uses as much as digits as its factorization.
1263215561 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 10800, while the sum is 32.
The square root of 1263215561 is about 35541.7439217605.
The cubic root of 1263215561 is about 1081.0003194812.
Note that the first 3 decimals are identical.
The spelling of 1263215561 in words is "one billion, two hundred sixty-three million, two hundred fifteen thousand, five hundred sixty-one".