1216191980 has 24 divisors (see below), whose sum is σ = 2558515680. Its totient is φ = 485617280.

The previous prime is 1216191971. The next prime is 1216191983. The reversal of 1216191980 is 891916121.

It is not an unprimeable number, because it can be changed into a prime (1216191983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42056 + ... + 64815.

It is an arithmetic number, because the mean of its divisors is an integer number (106604820).

Almost surely, 2^1216191980 is an apocalyptic number.

1216191980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216191980 is an abundant number, since it is smaller than the sum of its proper divisors (1342323700).

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

1216191980 is a wasteful number, since it uses less digits than its factorization.

1216191980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107449 (or 107447 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 38.

The square root of 1216191980 is about 34873.9441417228. The cubic root of 1216191980 is about 1067.4168275580.

The spelling of 1216191980 in words is "one billion, two hundred sixteen million, one hundred ninety-one thousand, nine hundred eighty".