1289391309 has 12 divisors (see below), whose sum is σ = 1863834336. Its totient is φ = 858957192.

The previous prime is 1289391307. The next prime is 1289391347. The reversal of 1289391309 is 9031939821.

It is a happy number.

It is not a de Polignac number, because 1289391309 - 2¹ = 1289391307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1289391307) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40099 + ... + 64704.

It is an arithmetic number, because the mean of its divisors is an integer number (155319528).

Almost surely, 2^1289391309 is an apocalyptic number.

It is an amenable number.

1289391309 is a deficient number, since it is larger than the sum of its proper divisors (574443027).

1289391309 is a wasteful number, since it uses less digits than its factorization.

1289391309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106176 (or 106173 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 1289391309 is about 35908.0953128957. The cubic root of 1289391309 is about 1088.4159886215.

The spelling of 1289391309 in words is "one billion, two hundred eighty-nine million, three hundred ninety-one thousand, three hundred nine".