It is a semiprime because it is the product of two primes.
It is a congruent number.
It is an unprimeable number.
Almost surely, 21291640158 is an apocalyptic number.
1291640158 is an equidigital number, since it uses as much as digits as its factorization.
1291640158 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 645820081.
The square root of 1291640158 is about 35939.3956265266. The cubic root of 1291640158 is about 1089.0483959578.
The spelling of 1291640158 in words is "one billion, two hundred ninety-one million, six hundred forty thousand, one hundred fifty-eight".