991203904 has 28 divisors (see below), whose sum is σ = 2082623724. Its totient is φ = 466448384.

The previous prime is 991203901. The next prime is 991203907. The reversal of 991203904 is 409302199.

It is an interprime number because it is at equal distance from previous prime (991203901) and next prime (991203907).

It can be written as a sum of positive squares in 2 ways, for example, as 605160000 + 386043904 = 24600^2 + 19648^2 .

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (991203901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454429 + ... + 456604.

Almost surely, 2^991203904 is an apocalyptic number.

It is an amenable number.

991203904 is an abundant number, since it is smaller than the sum of its proper divisors (1091419820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991203904 is a wasteful number, since it uses less digits than its factorization.

991203904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 911062 (or 911052 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 991203904 is about 31483.3909228342. The cubic root of 991203904 is about 997.0593289302.

The spelling of 991203904 in words is "nine hundred ninety-one million, two hundred three thousand, nine hundred four".