19911001012201 has 4 divisors (see below), whose sum is σ = 21442616474692. Its totient is φ = 18379385549712.

The previous prime is 19911001012153. The next prime is 19911001012207. The reversal of 19911001012201 is 10221010011991.

It is a happy number.

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 7934390408025 + 11976610604176 = 2816805^2 + 3460724^2 .

It is a cyclic number.

It is not a de Polignac number, because 19911001012201 - 2¹⁵ = 19911000979433 is a prime.

It is a super-2 number, since 2×19911001012201² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19911001012201.

It is not an unprimeable number, because it can be changed into a prime (19911001012207) 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 3 ways as a sum of consecutive naturals, for example, 765807731226 + ... + 765807731251.

It is an arithmetic number, because the mean of its divisors is an integer number (5360654118673).

Almost surely, 2^{19911001012201} is an apocalyptic number.

It is an amenable number.

19911001012201 is a deficient number, since it is larger than the sum of its proper divisors (1531615462491).

19911001012201 is a wasteful number, since it uses less digits than its factorization.

19911001012201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1531615462490.

The product of its (nonzero) digits is 324, while the sum is 28.

The spelling of 19911001012201 in words is "nineteen trillion, nine hundred eleven billion, one million, twelve thousand, two hundred one".