991372106 has 32 divisors (see below), whose sum is σ = 1531284480. Its totient is φ = 481244400.

The previous prime is 991372097. The next prime is 991372121. The reversal of 991372106 is 601273199.

It is a happy number.

991372106 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 991372106.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4367165 + ... + 4367391.

It is an arithmetic number, because the mean of its divisors is an integer number (47852640).

Almost surely, 2^991372106 is an apocalyptic number.

991372106 is a deficient number, since it is larger than the sum of its proper divisors (539912374).

991372106 is a wasteful number, since it uses less digits than its factorization.

991372106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650.

The product of its (nonzero) digits is 20412, while the sum is 38.

The square root of 991372106 is about 31486.0620910269. The cubic root of 991372106 is about 997.1157242851.

The spelling of 991372106 in words is "nine hundred ninety-one million, three hundred seventy-two thousand, one hundred six".