1661155 has 8 divisors (see below), whose sum is σ = 2110752. Its totient is φ = 1250688.

The previous prime is 1661141. The next prime is 1661159. The reversal of 1661155 is 5511661.

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 1661155 - 2⁵ = 1661123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661159) by changing a digit.

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, 9687 + ... + 9856.

It is an arithmetic number, because the mean of its divisors is an integer number (263844).

2^1661155 is an apocalyptic number.

1661155 is a deficient number, since it is larger than the sum of its proper divisors (449597).

1661155 is a wasteful number, since it uses less digits than its factorization.

1661155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19565.

The product of its digits is 900, while the sum is 25.

The square root of 1661155 is about 1288.8580216610. The cubic root of 1661155 is about 118.4322697453.

The spelling of 1661155 in words is "one million, six hundred sixty-one thousand, one hundred fifty-five".