661055 has 16 divisors (see below), whose sum is σ = 846720. Its totient is φ = 494592.

The previous prime is 661049. The next prime is 661061. The reversal of 661055 is 550166.

It is an interprime number because it is at equal distance from previous prime (661049) and next prime (661061).

It is a cyclic number.

It is not a de Polignac number, because 661055 - 2⁸ = 660799 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661055.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 6767 + ... + 6863.

It is an arithmetic number, because the mean of its divisors is an integer number (52920).

2⁶⁶¹⁰⁵⁵ is an apocalyptic number.

661055 is a deficient number, since it is larger than the sum of its proper divisors (185665).

661055 is a wasteful number, since it uses less digits than its factorization.

661055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 661055 is about 813.0528888086. The cubic root of 661055 is about 87.1122433768.

Subtracting from 661055 its reverse (550166), we obtain a square (110889 = 333²).

The spelling of 661055 in words is "six hundred sixty-one thousand, fifty-five".