991011903 has 8 divisors (see below), whose sum is σ = 1510113408. Its totient is φ = 566292504.

The previous prime is 991011887. The next prime is 991011907. The reversal of 991011903 is 309110199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991011903 - 2⁴ = 991011887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991011907) 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, 23595501 + ... + 23595542.

It is an arithmetic number, because the mean of its divisors is an integer number (188764176).

Almost surely, 2^991011903 is an apocalyptic number.

991011903 is a deficient number, since it is larger than the sum of its proper divisors (519101505).

991011903 is a wasteful number, since it uses less digits than its factorization.

991011903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47191053.

The product of its (nonzero) digits is 2187, while the sum is 33.

The square root of 991011903 is about 31480.3415324548. The cubic root of 991011903 is about 996.9949463649.

The spelling of 991011903 in words is "nine hundred ninety-one million, eleven thousand, nine hundred three".