1291864540 has 12 divisors (see below), whose sum is σ = 2712915576. Its totient is φ = 516745808.

The previous prime is 1291864517. The next prime is 1291864543. The reversal of 1291864540 is 454681921.

It is a junction number, because it is equal to n+sod(n) for n = 1291864493 and 1291864502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291864543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32296594 + ... + 32296633.

It is an arithmetic number, because the mean of its divisors is an integer number (226076298).

Almost surely, 2^1291864540 is an apocalyptic number.

1291864540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291864540 is an abundant number, since it is smaller than the sum of its proper divisors (1421051036).

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

1291864540 is a wasteful number, since it uses less digits than its factorization.

1291864540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64593236 (or 64593234 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 1291864540 is about 35942.5171628254. The cubic root of 1291864540 is about 1089.1114549832. Note that the first 3 decimals are identical.

The spelling of 1291864540 in words is "one billion, two hundred ninety-one million, eight hundred sixty-four thousand, five hundred forty".