1291689344 has 128 divisors (see below), whose sum is σ = 2908224000. Its totient is φ = 566425600.

The previous prime is 1291689337. The next prime is 1291689353. The reversal of 1291689344 is 4439861921.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×1291689344² = 3336922722806300672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8668982 + ... + 8669130.

It is an arithmetic number, because the mean of its divisors is an integer number (22720500).

Almost surely, 2^1291689344 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291689344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1454112000).

1291689344 is an abundant number, since it is smaller than the sum of its proper divisors (1616534656).

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

1291689344 is a wasteful number, since it uses less digits than its factorization.

1291689344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352 (or 340 counting only the distinct ones).

The product of its digits is 373248, while the sum is 47.

The square root of 1291689344 is about 35940.0799108739. The cubic root of 1291689344 is about 1089.0622195330.

The spelling of 1291689344 in words is "one billion, two hundred ninety-one million, six hundred eighty-nine thousand, three hundred forty-four".