991455389 has 8 divisors (see below), whose sum is σ = 1001366520. Its totient is φ = 981559296.

The previous prime is 991455383. The next prime is 991455401. The reversal of 991455389 is 983554199.

It is a happy number.

991455389 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 260564164 + 730891225 = 16142^2 + 27035^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 991455389 - 2⁸ = 991455133 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991455389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991455383) 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, 166349 + ... + 172205.

It is an arithmetic number, because the mean of its divisors is an integer number (125170815).

Almost surely, 2^991455389 is an apocalyptic number.

It is an amenable number.

991455389 is a deficient number, since it is larger than the sum of its proper divisors (9911131).

991455389 is a wasteful number, since it uses less digits than its factorization.

991455389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7519.

The product of its digits is 1749600, while the sum is 53.

The square root of 991455389 is about 31487.3846008207. The cubic root of 991455389 is about 997.1436453395.

The spelling of 991455389 in words is "nine hundred ninety-one million, four hundred fifty-five thousand, three hundred eighty-nine".