945991 has 4 divisors (see below), whose sum is σ = 995800. Its totient is φ = 896184.

The previous prime is 945983. The next prime is 946003. The reversal of 945991 is 199549.

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 945991 - 2³ = 945983 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 945991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (945941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24876 + ... + 24913.

It is an arithmetic number, because the mean of its divisors is an integer number (248950).

2⁹⁴⁵⁹⁹¹ is an apocalyptic number.

945991 is a deficient number, since it is larger than the sum of its proper divisors (49809).

945991 is a wasteful number, since it uses less digits than its factorization.

945991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49808.

The product of its digits is 14580, while the sum is 37.

The square root of 945991 is about 972.6206865988. The cubic root of 945991 is about 98.1662802499.

It can be divided in two parts, 945 and 991, that added together give a square (1936 = 44²).

The spelling of 945991 in words is "nine hundred forty-five thousand, nine hundred ninety-one".