1291928265 has 32 divisors (see below), whose sum is σ = 2340109440. Its totient is φ = 676024128.

The previous prime is 1291928263. The next prime is 1291928293. The reversal of 1291928265 is 5628291921.

It is a happy number.

It is not a de Polignac number, because 1291928265 - 2¹ = 1291928263 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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 1291928265.

It is not an unprimeable number, because it can be changed into a prime (1291928263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83127 + ... + 97436.

It is an arithmetic number, because the mean of its divisors is an integer number (73128420).

Almost surely, 2^1291928265 is an apocalyptic number.

1291928265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1291928265 is a deficient number, since it is larger than the sum of its proper divisors (1048181175).

1291928265 is a wasteful number, since it uses less digits than its factorization.

1291928265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180630 (or 180624 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 1291928265 is about 35943.4036368288. The cubic root of 1291928265 is about 1089.1293625589.

The spelling of 1291928265 in words is "one billion, two hundred ninety-one million, nine hundred twenty-eight thousand, two hundred sixty-five".