591621 has 4 divisors (see below), whose sum is σ = 788832. Its totient is φ = 394412.

The previous prime is 591611. The next prime is 591623. The reversal of 591621 is 126195.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-591621 is a prime.

It is a D-number.

591621 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 591591 and 591600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (591623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98601 + ... + 98606.

It is an arithmetic number, because the mean of its divisors is an integer number (197208).

2⁵⁹¹⁶²¹ is an apocalyptic number.

It is an amenable number.

591621 is a deficient number, since it is larger than the sum of its proper divisors (197211).

591621 is a wasteful number, since it uses less digits than its factorization.

591621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197210.

The product of its digits is 540, while the sum is 24.

The square root of 591621 is about 769.1690321379. The cubic root of 591621 is about 83.9488066753.

The spelling of 591621 in words is "five hundred ninety-one thousand, six hundred twenty-one".