1211221220001 has 32 divisors (see below), whose sum is σ = 1761823214592. Its totient is φ = 735683860800.

The previous prime is 1211221219993. The next prime is 1211221220009. The reversal of 1211221220001 is 1000221221121.

It is an interprime number because it is at equal distance from previous prime (1211221219993) and next prime (1211221220009).

It is not a de Polignac number, because 1211221220001 - 2³ = 1211221219993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211221220009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3224076 + ... + 3580098.

It is an arithmetic number, because the mean of its divisors is an integer number (55056975456).

Almost surely, 2^{1211221220001} is an apocalyptic number.

It is an amenable number.

1211221220001 is a deficient number, since it is larger than the sum of its proper divisors (550601994591).

1211221220001 is a wasteful number, since it uses less digits than its factorization.

1211221220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357173.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1211221220001 its reverse (1000221221121), we get a palindrome (2211442441122).

The spelling of 1211221220001 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred twenty thousand, one".