1221111201001 has 32 divisors (see below), whose sum is σ = 1344742502400. Its totient is φ = 1104674941440.

The previous prime is 1221111200957. The next prime is 1221111201083. The reversal of 1221111201001 is 1001021111221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221111201001 - 2²¹ = 1221109103849 is a prime.

It is a super-2 number, since 2×1221111201001² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221111271001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35655556 + ... + 35689786.

It is an arithmetic number, because the mean of its divisors is an integer number (42023203200).

Almost surely, 2^{1221111201001} is an apocalyptic number.

It is an amenable number.

1221111201001 is a deficient number, since it is larger than the sum of its proper divisors (123631301399).

1221111201001 is a wasteful number, since it uses less digits than its factorization.

1221111201001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35269.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 1221111201001 its reverse (1001021111221), we get a palindrome (2222132312222).

The spelling of 1221111201001 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred one thousand, one".