1221010020001 has 4 divisors (see below), whose sum is σ = 1232211946900. Its totient is φ = 1209808093104.

The previous prime is 1221010019993. The next prime is 1221010020067. The reversal of 1221010020001 is 1000200101221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1081701922401 + 139308097600 = 1040049^2 + 373240^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221010020001 - 2³ = 1221010019993 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221010020001.

It is not an unprimeable number, because it can be changed into a prime (1221010021001) 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, 5600963286 + ... + 5600963503.

It is an arithmetic number, because the mean of its divisors is an integer number (308052986725).

Almost surely, 2^{1221010020001} is an apocalyptic number.

It is an amenable number.

1221010020001 is a deficient number, since it is larger than the sum of its proper divisors (11201926899).

1221010020001 is a wasteful number, since it uses less digits than its factorization.

1221010020001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11201926898.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1221010020001 its reverse (1000200101221), we get a palindrome (2221210121222).

The spelling of 1221010020001 in words is "one trillion, two hundred twenty-one billion, ten million, twenty thousand, one".