1211021220001 has 4 divisors (see below), whose sum is σ = 1282257762372. Its totient is φ = 1139784677632.

The previous prime is 1211021219999. The next prime is 1211021220023. The reversal of 1211021220001 is 1000221201121.

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 1008867571776 + 202153648225 = 1004424^2 + 449615^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211021220001 - 2¹ = 1211021219999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211021250001) 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, 35618271160 + ... + 35618271193.

It is an arithmetic number, because the mean of its divisors is an integer number (320564440593).

Almost surely, 2^{1211021220001} is an apocalyptic number.

It is an amenable number.

1211021220001 is a deficient number, since it is larger than the sum of its proper divisors (71236542371).

1211021220001 is an equidigital number, since it uses as much as digits as its factorization.

1211021220001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71236542370.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1211021220001 its reverse (1000221201121), we get a palindrome (2211242421122).

The spelling of 1211021220001 in words is "one trillion, two hundred eleven billion, twenty-one million, two hundred twenty thousand, one".