1211555112 has 16 divisors (see below), whose sum is σ = 3028887840. Its totient is φ = 403851696.

The previous prime is 1211555087. The next prime is 1211555117. The reversal of 1211555112 is 2115551121.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 50481463 = 1211555112 / (1 + 2 + 1 + 1 + 5 + 5 + 5 + 1 + 1 + 2).

It is not an unprimeable number, because it can be changed into a prime (1211555117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25240708 + ... + 25240755.

It is an arithmetic number, because the mean of its divisors is an integer number (189305490).

Almost surely, 2^1211555112 is an apocalyptic number.

1211555112 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1211555112 is an abundant number, since it is smaller than the sum of its proper divisors (1817332728).

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

1211555112 is a wasteful number, since it uses less digits than its factorization.

1211555112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50481472 (or 50481468 counting only the distinct ones).

The product of its digits is 500, while the sum is 24.

The square root of 1211555112 is about 34807.4002476485. The cubic root of 1211555112 is about 1066.0585512041.

The spelling of 1211555112 in words is "one billion, two hundred eleven million, five hundred fifty-five thousand, one hundred twelve".