1291407989 has 4 divisors (see below), whose sum is σ = 1313296320. Its totient is φ = 1269519660.

The previous prime is 1291407983. The next prime is 1291407991. The reversal of 1291407989 is 9897041921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1291407989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291407983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10944077 + ... + 10944194.

It is an arithmetic number, because the mean of its divisors is an integer number (328324080).

Almost surely, 2^1291407989 is an apocalyptic number.

It is an amenable number.

1291407989 is a deficient number, since it is larger than the sum of its proper divisors (21888331).

1291407989 is an equidigital number, since it uses as much as digits as its factorization.

1291407989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21888330.

The product of its (nonzero) digits is 326592, while the sum is 50.

The square root of 1291407989 is about 35936.1654743519. The cubic root of 1291407989 is about 1088.9831408307.

The spelling of 1291407989 in words is "one billion, two hundred ninety-one million, four hundred seven thousand, nine hundred eighty-nine".