991545199 has 4 divisors (see below), whose sum is σ = 1023530560. Its totient is φ = 959559840.

The previous prime is 991545169. The next prime is 991545263.

It is a happy number.

991545199 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 991545199 - 2⁵ = 991545167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991545169) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 15992634 + ... + 15992695.

It is an arithmetic number, because the mean of its divisors is an integer number (255882640).

Almost surely, 2^991545199 is an apocalyptic number.

991545199 is a deficient number, since it is larger than the sum of its proper divisors (31985361).

991545199 is a wasteful number, since it uses less digits than its factorization.

991545199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31985360.

The product of its digits is 656100, while the sum is 52.

The square root of 991545199 is about 31488.8106952295. The cubic root of 991545199 is about 997.1737528521.

The spelling of 991545199 in words is "nine hundred ninety-one million, five hundred forty-five thousand, one hundred ninety-nine".