991199109910 has 16 divisors (see below), whose sum is σ = 1784172582000. Its totient is φ = 396476491936.

The previous prime is 991199109893. The next prime is 991199109919. The reversal of 991199109910 is 19901991199.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991199109919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1255641 + ... + 1886539.

It is an arithmetic number, because the mean of its divisors is an integer number (111510786375).

Almost surely, 2^991199109910 is an apocalyptic number.

991199109910 is a deficient number, since it is larger than the sum of its proper divisors (792973472090).

991199109910 is a wasteful number, since it uses less digits than its factorization.

991199109910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788015.

The product of its (nonzero) digits is 531441, while the sum is 58.

It can be divided in two parts, 99119 and 9109910, that added together give a palindrome (9209029).

The spelling of 991199109910 in words is "nine hundred ninety-one billion, one hundred ninety-nine million, one hundred nine thousand, nine hundred ten".