991100054555 has 32 divisors (see below), whose sum is σ = 1285024231680. Its totient is φ = 729482889600.

The previous prime is 991100054543. The next prime is 991100054591. The reversal of 991100054555 is 555450001199.

It is a happy number.

It is not a de Polignac number, because 991100054555 - 2⁸ = 991100054299 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 25102580 + ... + 25142030.

It is an arithmetic number, because the mean of its divisors is an integer number (40157007240).

Almost surely, 2^991100054555 is an apocalyptic number.

991100054555 is a deficient number, since it is larger than the sum of its proper divisors (293924177125).

991100054555 is a wasteful number, since it uses less digits than its factorization.

991100054555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40731.

The product of its (nonzero) digits is 202500, while the sum is 44.

The spelling of 991100054555 in words is "nine hundred ninety-one billion, one hundred million, fifty-four thousand, five hundred fifty-five".