661755 has 16 divisors (see below), whose sum is σ = 1069344. Its totient is φ = 349440.

The previous prime is 661741. The next prime is 661769. The reversal of 661755 is 557166.

It is an interprime number because it is at equal distance from previous prime (661741) and next prime (661769).

It is not a de Polignac number, because 661755 - 2¹⁰ = 660731 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661755.

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, 2215 + ... + 2495.

It is an arithmetic number, because the mean of its divisors is an integer number (66834).

2⁶⁶¹⁷⁵⁵ is an apocalyptic number.

661755 is a deficient number, since it is larger than the sum of its proper divisors (407589).

661755 is a wasteful number, since it uses less digits than its factorization.

661755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446.

The product of its digits is 6300, while the sum is 30.

The square root of 661755 is about 813.4832512105. The cubic root of 661755 is about 87.1429806374.

The spelling of 661755 in words is "six hundred sixty-one thousand, seven hundred fifty-five".