1221001004020 has 24 divisors (see below), whose sum is σ = 2930402409984. Its totient is φ = 418628915616.

The previous prime is 1221001004009. The next prime is 1221001004057. The reversal of 1221001004020 is 204001001221.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4360717732 + ... + 4360718011.

It is an arithmetic number, because the mean of its divisors is an integer number (122100100416).

Almost surely, 2^{1221001004020} is an apocalyptic number.

1221001004020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221001004020 is an abundant number, since it is smaller than the sum of its proper divisors (1709401405964).

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

1221001004020 is a wasteful number, since it uses less digits than its factorization.

1221001004020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8721435759 (or 8721435757 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 1221001004020 its reverse (204001001221), we get a palindrome (1425002005241).

The spelling of 1221001004020 in words is "one trillion, two hundred twenty-one billion, one million, four thousand, twenty".