1221201001020 has 768 divisors, whose sum is σ = 4762674008064. Its totient is φ = 225607680000.

The previous prime is 1221201000979. The next prime is 1221201001133. The reversal of 1221201001020 is 201001021221.

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 = 1221201000987 and 1221201001005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 224441500 + ... + 224446940.

It is an arithmetic number, because the mean of its divisors is an integer number (6201398448).

Almost surely, 2^{1221201001020} is an apocalyptic number.

1221201001020 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 1221201001020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2381337004032).

1221201001020 is an abundant number, since it is smaller than the sum of its proper divisors (3541473007044).

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

1221201001020 is a wasteful number, since it uses less digits than its factorization.

1221201001020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5622 (or 5620 counting only the distinct ones).

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

Adding to 1221201001020 its reverse (201001021221), we get a palindrome (1422202022241).

The spelling of 1221201001020 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one thousand, twenty".