991900909910 has 32 divisors (see below), whose sum is σ = 1788089022720. Its totient is φ = 396167921152.

The previous prime is 991900909897. The next prime is 991900909919. The reversal of 991900909910 is 19909009199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991900909919) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28769402 + ... + 28803858.

It is an arithmetic number, because the mean of its divisors is an integer number (55877781960).

Almost surely, 2^991900909910 is an apocalyptic number.

991900909910 is a deficient number, since it is larger than the sum of its proper divisors (796188112810).

991900909910 is a wasteful number, since it uses less digits than its factorization.

991900909910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38680.

The product of its (nonzero) digits is 531441, while the sum is 56.

The spelling of 991900909910 in words is "nine hundred ninety-one billion, nine hundred million, nine hundred nine thousand, nine hundred ten".