5591991 has 4 divisors (see below), whose sum is σ = 7455992. Its totient is φ = 3727992.

The previous prime is 5591987. The next prime is 5592001. The reversal of 5591991 is 1991955.

5591991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 5591991 - 2² = 5591987 is a prime.

It is a D-number.

It is a Duffinian number.

5591991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5591941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 931996 + ... + 932001.

It is an arithmetic number, because the mean of its divisors is an integer number (1863998).

Almost surely, 2^5591991 is an apocalyptic number.

5591991 is a deficient number, since it is larger than the sum of its proper divisors (1864001).

5591991 is a wasteful number, since it uses less digits than its factorization.

5591991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1864000.

The product of its digits is 18225, while the sum is 39.

The square root of 5591991 is about 2364.7390976596. The cubic root of 5591991 is about 177.4961025396.

It can be divided in two parts, 55 and 91991, that multiplied together give a palindrome (5059505).

The spelling of 5591991 in words is "five million, five hundred ninety-one thousand, nine hundred ninety-one".