1166556780 has 72 divisors (see below), whose sum is σ = 3692418912. Its totient is φ = 297555456.

The previous prime is 1166556707. The next prime is 1166556821. The reversal of 1166556780 is 876556611.

1166556780 is a `hidden beast` number, since 1 + 1 + 6 + 6 + 5 + 567 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136749 + ... + 145028.

It is an arithmetic number, because the mean of its divisors is an integer number (51283596).

Almost surely, 2^1166556780 is an apocalyptic number.

1166556780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1166556780 is an abundant number, since it is smaller than the sum of its proper divisors (2525862132).

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

1166556780 is a wasteful number, since it uses less digits than its factorization.

1166556780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281815 (or 281810 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The square root of 1166556780 is about 34154.8939392293. The cubic root of 1166556780 is about 1052.6935469668.

The spelling of 1166556780 in words is "one billion, one hundred sixty-six million, five hundred fifty-six thousand, seven hundred eighty".