661835 has 4 divisors (see below), whose sum is σ = 794208. Its totient is φ = 529464.

The previous prime is 661823. The next prime is 661849. The reversal of 661835 is 538166.

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

It is a cyclic number.

It is not a de Polignac number, because 661835 - 2¹⁰ = 660811 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661798 and 661807.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66179 + ... + 66188.

It is an arithmetic number, because the mean of its divisors is an integer number (198552).

2⁶⁶¹⁸³⁵ is an apocalyptic number.

661835 is a deficient number, since it is larger than the sum of its proper divisors (132373).

661835 is a wasteful number, since it uses less digits than its factorization.

661835 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132372.

The product of its digits is 4320, while the sum is 29.

The square root of 661835 is about 813.5324209889. The cubic root of 661835 is about 87.1464920868.

The spelling of 661835 in words is "six hundred sixty-one thousand, eight hundred thirty-five".