1209999980 has 24 divisors (see below), whose sum is σ = 2904000288. Its totient is φ = 414857088.

The previous prime is 1209999943. The next prime is 1209999997. The reversal of 1209999980 is 899999021.

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4321289 + ... + 4321568.

It is an arithmetic number, because the mean of its divisors is an integer number (121000012).

Almost surely, 2^1209999980 is an apocalyptic number.

1209999980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1209999980 is an abundant number, since it is smaller than the sum of its proper divisors (1694000308).

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

1209999980 is a wasteful number, since it uses less digits than its factorization.

1209999980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8642873 (or 8642871 counting only the distinct ones).

The product of its (nonzero) digits is 944784, while the sum is 56.

The square root of 1209999980 is about 34785.0539743724. The cubic root of 1209999980 is about 1065.6022308955.

The spelling of 1209999980 in words is "one billion, two hundred nine million, nine hundred ninety-nine thousand, nine hundred eighty".