1263391289 has 2 divisors, whose sum is σ = 1263391290. Its totient is φ = 1263391288.

The previous prime is 1263391279. The next prime is 1263391309. The reversal of 1263391289 is 9821933621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 852640000 + 410751289 = 29200^2 + 20267^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263391289 - 2⁴ = 1263391273 is a prime.

It is not a weakly prime, because it can be changed into another prime (1263391279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631695644 + 631695645.

It is an arithmetic number, because the mean of its divisors is an integer number (631695645).

Almost surely, 2^1263391289 is an apocalyptic number.

It is an amenable number.

1263391289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263391289 is an equidigital number, since it uses as much as digits as its factorization.

1263391289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 44.

The square root of 1263391289 is about 35544.2159710972. The cubic root of 1263391289 is about 1081.0504437360.

The spelling of 1263391289 in words is "one billion, two hundred sixty-three million, three hundred ninety-one thousand, two hundred eighty-nine".