1211111980 has 48 divisors (see below), whose sum is σ = 2797280640. Its totient is φ = 437660928.

The previous prime is 1211111963. The next prime is 1211111981. The reversal of 1211111980 is 891111121.

It is not an unprimeable number, because it can be changed into a prime (1211111981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37335 + ... + 61774.

It is an arithmetic number, because the mean of its divisors is an integer number (58276680).

Almost surely, 2^1211111980 is an apocalyptic number.

1211111980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211111980 is an abundant number, since it is smaller than the sum of its proper divisors (1586168660).

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

1211111980 is a wasteful number, since it uses less digits than its factorization.

1211111980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99178 (or 99176 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 25.

The square root of 1211111980 is about 34801.0341800355. The cubic root of 1211111980 is about 1065.9285633729.

The spelling of 1211111980 in words is "one billion, two hundred eleven million, one hundred eleven thousand, nine hundred eighty".