1221020020001 has 16 divisors (see below), whose sum is σ = 1308227324160. Its totient is φ = 1136206550160.

The previous prime is 1221020019937. The next prime is 1221020020007. The reversal of 1221020020001 is 1000200201221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221020020001 - 2⁶ = 1221020019937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221020020007) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 940355 + ... + 1823816.

It is an arithmetic number, because the mean of its divisors is an integer number (81764207760).

Almost surely, 2^{1221020020001} is an apocalyptic number.

It is an amenable number.

1221020020001 is a deficient number, since it is larger than the sum of its proper divisors (87207304159).

1221020020001 is a wasteful number, since it uses less digits than its factorization.

1221020020001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2764604.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1221020020001 its reverse (1000200201221), we get a palindrome (2221220221222).

The spelling of 1221020020001 in words is "one trillion, two hundred twenty-one billion, twenty million, twenty thousand, one".