1211211221001 has 8 divisors (see below), whose sum is σ = 1615021283040. Its totient is φ = 807437653152.

The previous prime is 1211211220937. The next prime is 1211211221039. The reversal of 1211211221001 is 1001221121121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1211211221001 - 2⁶ = 1211211220937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211211221081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9046011 + ... + 9178928.

It is an arithmetic number, because the mean of its divisors is an integer number (201877660380).

Almost surely, 2^{1211211221001} is an apocalyptic number.

It is an amenable number.

1211211221001 is a deficient number, since it is larger than the sum of its proper divisors (403810062039).

1211211221001 is a wasteful number, since it uses less digits than its factorization.

1211211221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18247095.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211211221001 its reverse (1001221121121), we get a palindrome (2212432342122).

The spelling of 1211211221001 in words is "one trillion, two hundred eleven billion, two hundred eleven million, two hundred twenty-one thousand, one".