1261866163 has 2 divisors, whose sum is σ = 1261866164. Its totient is φ = 1261866162.

The previous prime is 1261866149. The next prime is 1261866197. The reversal of 1261866163 is 3616681621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1261866163 - 2²⁵ = 1228311731 is a prime.

It is not a weakly prime, because it can be changed into another prime (1261866103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630933081 + 630933082.

It is an arithmetic number, because the mean of its divisors is an integer number (630933082).

Almost surely, 2^1261866163 is an apocalyptic number.

1261866163 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261866163 is an equidigital number, since it uses as much as digits as its factorization.

1261866163 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 40.

The square root of 1261866163 is about 35522.7555659749. The cubic root of 1261866163 is about 1080.6152652780.

The spelling of 1261866163 in words is "one billion, two hundred sixty-one million, eight hundred sixty-six thousand, one hundred sixty-three".