661911 has 8 divisors (see below), whose sum is σ = 897264. Its totient is φ = 433920.

The previous prime is 661909. The next prime is 661931. The reversal of 661911 is 119166.

661911 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 661911 - 2¹ = 661909 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661911.

It is not an unprimeable number, because it can be changed into a prime (661931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1626 + ... + 1991.

It is an arithmetic number, because the mean of its divisors is an integer number (112158).

2⁶⁶¹⁹¹¹ is an apocalyptic number.

661911 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

661911 is a deficient number, since it is larger than the sum of its proper divisors (235353).

661911 is a wasteful number, since it uses less digits than its factorization.

661911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3681.

The product of its digits is 324, while the sum is 24.

The square root of 661911 is about 813.5791295258. The cubic root of 661911 is about 87.1498277016.

The spelling of 661911 in words is "six hundred sixty-one thousand, nine hundred eleven".