661814 has 4 divisors (see below), whose sum is σ = 992724. Its totient is φ = 330906.

The previous prime is 661777. The next prime is 661823. The reversal of 661814 is 418166.

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

It is a Curzon number.

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 661814.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165452 + ... + 165455.

It is an arithmetic number, because the mean of its divisors is an integer number (248181).

2⁶⁶¹⁸¹⁴ is an apocalyptic number.

661814 is a deficient number, since it is larger than the sum of its proper divisors (330910).

661814 is a wasteful number, since it uses less digits than its factorization.

661814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330909.

The product of its digits is 1152, while the sum is 26.

The square root of 661814 is about 813.5195142097. The cubic root of 661814 is about 87.1455703587.

The spelling of 661814 in words is "six hundred sixty-one thousand, eight hundred fourteen".