601991 has 4 divisors (see below), whose sum is σ = 648312. Its totient is φ = 555672.

The previous prime is 601981. The next prime is 602029. The reversal of 601991 is 199106.

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

It is a de Polignac number, because none of the positive numbers 2^k-601991 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a zygodrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 601991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (601961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23141 + ... + 23166.

It is an arithmetic number, because the mean of its divisors is an integer number (162078).

2⁶⁰¹⁹⁹¹ is an apocalyptic number.

601991 is a deficient number, since it is larger than the sum of its proper divisors (46321).

601991 is a wasteful number, since it uses less digits than its factorization.

601991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46320.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 601991 is about 775.8807898125. The cubic root of 601991 is about 84.4364565518.

The spelling of 601991 in words is "six hundred one thousand, nine hundred ninety-one".