991745503 has 16 divisors (see below), whose sum is σ = 1165925376. Its totient is φ = 826028640.

The previous prime is 991745497. The next prime is 991745551. The reversal of 991745503 is 305547199.

It is a cyclic number.

It is not a de Polignac number, because 991745503 - 2⁵ = 991745471 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 991745503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991745203) 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, 21450 + ... + 49432.

It is an arithmetic number, because the mean of its divisors is an integer number (72870336).

Almost surely, 2^991745503 is an apocalyptic number.

991745503 is a deficient number, since it is larger than the sum of its proper divisors (174179873).

991745503 is a wasteful number, since it uses less digits than its factorization.

991745503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28134.

The product of its (nonzero) digits is 170100, while the sum is 43.

The square root of 991745503 is about 31491.9910929747. The cubic root of 991745503 is about 997.2408953429.

The spelling of 991745503 in words is "nine hundred ninety-one million, seven hundred forty-five thousand, five hundred three".