1213111020 has 48 divisors (see below), whose sum is σ = 3705504768. Its totient is φ = 294087360.

The previous prime is 1213110989. The next prime is 1213111021. The reversal of 1213111020 is 201113121.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1213110987 and 1213111005.

It is not an unprimeable number, because it can be changed into a prime (1213111021) 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, 918364 + ... + 919683.

It is an arithmetic number, because the mean of its divisors is an integer number (77198016).

Almost surely, 2^1213111020 is an apocalyptic number.

1213111020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1213111020 is an abundant number, since it is smaller than the sum of its proper divisors (2492393748).

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

1213111020 is a wasteful number, since it uses less digits than its factorization.

1213111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1838070 (or 1838068 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1213111020 is about 34829.7433237743. The cubic root of 1213111020 is about 1066.5147086047.

Adding to 1213111020 its reverse (201113121), we get a palindrome (1414224141).

The spelling of 1213111020 in words is "one billion, two hundred thirteen million, one hundred eleven thousand, twenty".