1220012100 has 108 divisors (see below), whose sum is σ = 3927520324. Its totient is φ = 316535040.

The previous prime is 1220012093. The next prime is 1220012119. The reversal of 1220012100 is 12100221.

It can be written as a sum of positive squares in 6 ways, for example, as 186624 + 1219825476 = 432^2 + 34926^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 14982 + ... + 51618.

Almost surely, 2^1220012100 is an apocalyptic number.

1220012100 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 1220012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1963760162).

1220012100 is an abundant number, since it is smaller than the sum of its proper divisors (2707508224).

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

1220012100 is a wasteful number, since it uses less digits than its factorization.

1220012100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36694 (or 36684 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1220012100 is about 34928.6716037126. The cubic root of 1220012100 is about 1068.5332627082.

Adding to 1220012100 its reverse (12100221), we get a palindrome (1232112321).

The spelling of 1220012100 in words is "one billion, two hundred twenty million, twelve thousand, one hundred".