1200121020 has 144 divisors (see below), whose sum is σ = 4197735360. Its totient is φ = 271853568.

The previous prime is 1200121019. The next prime is 1200121057. The reversal of 1200121020 is 201210021.

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

It is a junction number, because it is equal to n+sod(n) for n = 1200120993 and 1200121011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 138166 + ... + 146594.

It is an arithmetic number, because the mean of its divisors is an integer number (29150940).

Almost surely, 2^1200121020 is an apocalyptic number.

1200121020 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 1200121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2098867680).

1200121020 is an abundant number, since it is smaller than the sum of its proper divisors (2997614340).

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

1200121020 is a wasteful number, since it uses less digits than its factorization.

1200121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8564 (or 8559 counting only the distinct ones).

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

The square root of 1200121020 is about 34642.7628805787. The cubic root of 1200121020 is about 1062.6942910207.

Adding to 1200121020 its reverse (201210021), we get a palindrome (1401331041).

The spelling of 1200121020 in words is "one billion, two hundred million, one hundred twenty-one thousand, twenty".