1211001021999 has 12 divisors (see below), whose sum is σ = 1809541757400. Its totient is φ = 779494910544.

The previous prime is 1211001021959. The next prime is 1211001022001. The reversal of 1211001021999 is 9991201001121.

It is not a de Polignac number, because 1211001021999 - 2¹¹ = 1211001019951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211001021959) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2319925069 + ... + 2319925590.

It is an arithmetic number, because the mean of its divisors is an integer number (150795146450).

Almost surely, 2^{1211001021999} is an apocalyptic number.

1211001021999 is a deficient number, since it is larger than the sum of its proper divisors (598540735401).

1211001021999 is a wasteful number, since it uses less digits than its factorization.

1211001021999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4639850694 (or 4639850691 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 36.

The spelling of 1211001021999 in words is "one trillion, two hundred eleven billion, one million, twenty-one thousand, nine hundred ninety-nine".