1211111020 has 24 divisors (see below), whose sum is σ = 2906666784. Its totient is φ = 415238016.

The previous prime is 1211110987. The next prime is 1211111029. The reversal of 1211111020 is 201111121.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 1211110988 and 1211111006.

It is not an unprimeable number, because it can be changed into a prime (1211111029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4325257 + ... + 4325536.

It is an arithmetic number, because the mean of its divisors is an integer number (121111116).

Almost surely, 2^1211111020 is an apocalyptic number.

1211111020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211111020 is an abundant number, since it is smaller than the sum of its proper divisors (1695555764).

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

1211111020 is a wasteful number, since it uses less digits than its factorization.

1211111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8650809 (or 8650807 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

The square root of 1211111020 is about 34801.0203873392. The cubic root of 1211111020 is about 1065.9282817331.

Adding to 1211111020 its reverse (201111121), we get a palindrome (1412222141).

The spelling of 1211111020 in words is "one billion, two hundred eleven million, one hundred eleven thousand, twenty".