991633945 has 8 divisors (see below), whose sum is σ = 1210129920. Its totient is φ = 779861040.

The previous prime is 991633897. The next prime is 991633961. The reversal of 991633945 is 549336199.

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

It is not a de Polignac number, because 991633945 - 2¹⁷ = 991502873 is a prime.

It is a super-3 number, since 3×991633945³ (a number of 28 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1680441 + ... + 1681030.

It is an arithmetic number, because the mean of its divisors is an integer number (151266240).

Almost surely, 2^991633945 is an apocalyptic number.

It is an amenable number.

991633945 is a deficient number, since it is larger than the sum of its proper divisors (218495975).

991633945 is a wasteful number, since it uses less digits than its factorization.

991633945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3361535.

The product of its digits is 787320, while the sum is 49.

The square root of 991633945 is about 31490.2198309253. The cubic root of 991633945 is about 997.2035018882.

The spelling of 991633945 in words is "nine hundred ninety-one million, six hundred thirty-three thousand, nine hundred forty-five".