661155 has 16 divisors (see below), whose sum is σ = 1154304. Its totient is φ = 320480.

The previous prime is 661139. The next prime is 661183. The reversal of 661155 is 551166.

It is not a de Polignac number, because 661155 - 2⁴ = 661139 is a prime.

It is a zygodrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1839 + ... + 2168.

It is an arithmetic number, because the mean of its divisors is an integer number (72144).

2⁶⁶¹¹⁵⁵ is an apocalyptic number.

661155 is a deficient number, since it is larger than the sum of its proper divisors (493149).

661155 is a wasteful number, since it uses less digits than its factorization.

661155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4026.

The product of its digits is 900, while the sum is 24.

The square root of 661155 is about 813.1143830975. The cubic root of 661155 is about 87.1166357421.

It can be divided in two parts, 6611 and 55, that added together give a palindrome (6666).

The spelling of 661155 in words is "six hundred sixty-one thousand, one hundred fifty-five".