1221110020 has 96 divisors (see below), whose sum is σ = 2931344640. Its totient is φ = 423836160.

The previous prime is 1221109973. The next prime is 1221110071. The reversal of 1221110020 is 200111221.

It is a super-2 number, since 2×1221110020² = 2982219361888800800, which contains 22 as substring.

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 = 1221109979 and 1221110006.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 351090 + ... + 354550.

It is an arithmetic number, because the mean of its divisors is an integer number (30534840).

Almost surely, 2^1221110020 is an apocalyptic number.

1221110020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221110020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1465672320).

1221110020 is an abundant number, since it is smaller than the sum of its proper divisors (1710234620).

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

1221110020 is a wasteful number, since it uses less digits than its factorization.

1221110020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3565 (or 3563 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1221110020 is about 34944.3846705018. The cubic root of 1221110020 is about 1068.8537000480.

Adding to 1221110020 its reverse (200111221), we get a palindrome (1421221241).

The spelling of 1221110020 in words is "one billion, two hundred twenty-one million, one hundred ten thousand, twenty".