1291749540 has 192 divisors, whose sum is σ = 3870720000. Its totient is φ = 321384960.

The previous prime is 1291749521. The next prime is 1291749559. The reversal of 1291749540 is 459471921.

It is an interprime number because it is at equal distance from previous prime (1291749521) and next prime (1291749559).

It is a junction number, because it is equal to n+sod(n) for n = 1291749492 and 1291749501.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8669386 + ... + 8669534.

It is an arithmetic number, because the mean of its divisors is an integer number (20160000).

Almost surely, 2^1291749540 is an apocalyptic number.

1291749540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291749540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1935360000).

1291749540 is an abundant number, since it is smaller than the sum of its proper divisors (2578970460).

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

1291749540 is a wasteful number, since it uses less digits than its factorization.

1291749540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 1291749540 is about 35940.9173505630. The cubic root of 1291749540 is about 1089.0791369575.

The spelling of 1291749540 in words is "one billion, two hundred ninety-one million, seven hundred forty-nine thousand, five hundred forty".