1221010020021 has 12 divisors (see below), whose sum is σ = 1789469230976. Its totient is φ = 740006072520.

The previous prime is 1221010019993. The next prime is 1221010020067. The reversal of 1221010020021 is 1200200101221.

It is not a de Polignac number, because 1221010020021 - 2¹³ = 1221010011829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221010019979 and 1221010020006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221010020421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1681831621 + ... + 1681832346.

Almost surely, 2^{1221010020021} is an apocalyptic number.

1221010020021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221010020021 is a deficient number, since it is larger than the sum of its proper divisors (568459210955).

1221010020021 is a wasteful number, since it uses less digits than its factorization.

1221010020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3363663992 (or 3363663981 counting only the distinct ones).

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

Adding to 1221010020021 its reverse (1200200101221), we get a palindrome (2421210121242).

The spelling of 1221010020021 in words is "one trillion, two hundred twenty-one billion, ten million, twenty thousand, twenty-one".