1221001200021 has 8 divisors (see below), whose sum is σ = 1672001643424. Its totient is φ = 792000778320.

The previous prime is 1221001200019. The next prime is 1221001200037. The reversal of 1221001200021 is 1200021001221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221001200021 - 2¹ = 1221001200019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221001210021) by changing a digit.

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, 5500005295 + ... + 5500005516.

It is an arithmetic number, because the mean of its divisors is an integer number (209000205428).

Almost surely, 2^{1221001200021} is an apocalyptic number.

It is an amenable number.

1221001200021 is a deficient number, since it is larger than the sum of its proper divisors (451000443403).

1221001200021 is a wasteful number, since it uses less digits than its factorization.

1221001200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11000010851.

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

Adding to 1221001200021 its reverse (1200021001221), we get a palindrome (2421022201242).

The spelling of 1221001200021 in words is "one trillion, two hundred twenty-one billion, one million, two hundred thousand, twenty-one".