1291989258 has 128 divisors (see below), whose sum is σ = 3447705600. Its totient is φ = 350640576.

The previous prime is 1291989247. The next prime is 1291989271. The reversal of 1291989258 is 8529891921.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1503633 + ... + 1504491.

It is an arithmetic number, because the mean of its divisors is an integer number (26935200).

Almost surely, 2^1291989258 is an apocalyptic number.

1291989258 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291989258, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1723852800).

1291989258 is an abundant number, since it is smaller than the sum of its proper divisors (2155716342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1291989258 is a wasteful number, since it uses less digits than its factorization.

1291989258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1073 (or 1067 counting only the distinct ones).

The product of its digits is 933120, while the sum is 54.

The square root of 1291989258 is about 35944.2520856951. The cubic root of 1291989258 is about 1089.1465018547.

The spelling of 1291989258 in words is "one billion, two hundred ninety-one million, nine hundred eighty-nine thousand, two hundred fifty-eight".