1221020022021 has 4 divisors (see below), whose sum is σ = 1628026696032. Its totient is φ = 814013348012.

The previous prime is 1221020021999. The next prime is 1221020022031. The reversal of 1221020022021 is 1202200201221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221020022021 - 2¹⁵ = 1221019989253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020022031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203503337001 + ... + 203503337006.

It is an arithmetic number, because the mean of its divisors is an integer number (407006674008).

Almost surely, 2^{1221020022021} is an apocalyptic number.

It is an amenable number.

1221020022021 is a deficient number, since it is larger than the sum of its proper divisors (407006674011).

1221020022021 is an equidigital number, since it uses as much as digits as its factorization.

1221020022021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407006674010.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 1221020022021 its reverse (1202200201221), we get a palindrome (2423220223242).

The spelling of 1221020022021 in words is "one trillion, two hundred twenty-one billion, twenty million, twenty-two thousand, twenty-one".