991386575 has 12 divisors (see below), whose sum is σ = 1243134720. Its totient is φ = 784196160.

The previous prime is 991386551. The next prime is 991386577. The reversal of 991386575 is 575683199.

It is not a de Polignac number, because 991386575 - 2¹² = 991382479 is a prime.

It is a hoax number, since the sum of its digits (53) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991386577) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 220559 + ... + 225008.

It is an arithmetic number, because the mean of its divisors is an integer number (103594560).

Almost surely, 2^991386575 is an apocalyptic number.

991386575 is a deficient number, since it is larger than the sum of its proper divisors (251748145).

991386575 is a wasteful number, since it uses less digits than its factorization.

991386575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445666 (or 445661 counting only the distinct ones).

The product of its digits is 2041200, while the sum is 53.

The square root of 991386575 is about 31486.2918585215. The cubic root of 991386575 is about 997.1205752040.

The spelling of 991386575 in words is "nine hundred ninety-one million, three hundred eighty-six thousand, five hundred seventy-five".