1291278180 has 48 divisors (see below), whose sum is σ = 3828263040. Its totient is φ = 324085248.

The previous prime is 1291278179. The next prime is 1291278199. The reversal of 1291278180 is 818721921.

It is a super-2 number, since 2×1291278180² = 3334798676288224800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 631960 + ... + 633999.

It is an arithmetic number, because the mean of its divisors is an integer number (79755480).

Almost surely, 2^1291278180 is an apocalyptic number.

1291278180 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291278180 is an abundant number, since it is smaller than the sum of its proper divisors (2536984860).

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

1291278180 is a wasteful number, since it uses less digits than its factorization.

1291278180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1265988 (or 1265986 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 39.

The square root of 1291278180 is about 35934.3593236334. The cubic root of 1291278180 is about 1088.9466523493.

The spelling of 1291278180 in words is "one billion, two hundred ninety-one million, two hundred seventy-eight thousand, one hundred eighty".