1291137440 has 48 divisors (see below), whose sum is σ = 3054338280. Its totient is φ = 515773440.

The previous prime is 1291137431. The next prime is 1291137451. The reversal of 1291137440 is 447311921.

It can be written as a sum of positive squares in 4 ways, for example, as 1147041424 + 144096016 = 33868^2 + 12004^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 1291137397 and 1291137406.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126446 + ... + 136274.

Almost surely, 2^1291137440 is an apocalyptic number.

1291137440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291137440 is an abundant number, since it is smaller than the sum of its proper divisors (1763200840).

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

1291137440 is an equidigital number, since it uses as much as digits as its factorization.

1291137440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10665 (or 10657 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 1291137440 is about 35932.4009773909. The cubic root of 1291137440 is about 1088.9070884706.

The spelling of 1291137440 in words is "one billion, two hundred ninety-one million, one hundred thirty-seven thousand, four hundred forty".