1221001120020 has 192 divisors, whose sum is σ = 3828562698240. Its totient is φ = 288249062400.

The previous prime is 1221001120019. The next prime is 1221001120051. The reversal of 1221001120020 is 200211001221.

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 = 1221001119978 and 1221001120005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3645825 + ... + 3966615.

It is an arithmetic number, because the mean of its divisors is an integer number (19940430720).

Almost surely, 2^{1221001120020} is an apocalyptic number.

1221001120020 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 1221001120020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1914281349120).

1221001120020 is an abundant number, since it is smaller than the sum of its proper divisors (2607561578220).

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

1221001120020 is a wasteful number, since it uses less digits than its factorization.

1221001120020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320966 (or 320964 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 1221001120020 its reverse (200211001221), we get a palindrome (1421212121241).

The spelling of 1221001120020 in words is "one trillion, two hundred twenty-one billion, one million, one hundred twenty thousand, twenty".