1291497165 has 144 divisors (see below), whose sum is σ = 2838326400. Its totient is φ = 539529984.

The previous prime is 1291497149. The next prime is 1291497187. The reversal of 1291497165 is 5617941921.

1291497165 is a `hidden beast` number, since 12 + 91 + 497 + 1 + 65 = 666.

It is not a de Polignac number, because 1291497165 - 2⁴ = 1291497149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1291497165.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1214424 + ... + 1215486.

It is an arithmetic number, because the mean of its divisors is an integer number (19710600).

Almost surely, 2^1291497165 is an apocalyptic number.

1291497165 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1291497165 is an abundant number, since it is smaller than the sum of its proper divisors (1546829235).

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

1291497165 is a wasteful number, since it uses less digits than its factorization.

1291497165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136 (or 1126 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 1291497165 is about 35937.4062085733. The cubic root of 1291497165 is about 1089.0082062183.

The spelling of 1291497165 in words is "one billion, two hundred ninety-one million, four hundred ninety-seven thousand, one hundred sixty-five".