661355 has 8 divisors (see below), whose sum is σ = 798000. Its totient is φ = 526176.

The previous prime is 661343. The next prime is 661361. The reversal of 661355 is 553166.

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

It is a cyclic number.

It is not a de Polignac number, because 661355 - 2⁸ = 661099 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1556 + ... + 1934.

It is an arithmetic number, because the mean of its divisors is an integer number (99750).

2⁶⁶¹³⁵⁵ is an apocalyptic number.

661355 is a deficient number, since it is larger than the sum of its proper divisors (136645).

661355 is a wasteful number, since it uses less digits than its factorization.

661355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733.

The product of its digits is 2700, while the sum is 26.

The square root of 661355 is about 813.2373577253. The cubic root of 661355 is about 87.1254191442.

The spelling of 661355 in words is "six hundred sixty-one thousand, three hundred fifty-five".