991111121002 has 16 divisors (see below), whose sum is σ = 1501031644200. Its totient is φ = 490771638720.

The previous prime is 991111120997. The next prime is 991111121053. The reversal of 991111121002 is 200121111199.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 945097009921 + 46014111081 = 972161^2 + 214509^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 647649 + ... + 1549732.

Almost surely, 2^991111121002 is an apocalyptic number.

991111121002 is a deficient number, since it is larger than the sum of its proper divisors (509920523198).

991111121002 is a wasteful number, since it uses less digits than its factorization.

991111121002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2199561.

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

The spelling of 991111121002 in words is "nine hundred ninety-one billion, one hundred eleven million, one hundred twenty-one thousand, two".