1661158 has 4 divisors (see below), whose sum is σ = 2491740. Its totient is φ = 830578.

The previous prime is 1661141. The next prime is 1661159. The reversal of 1661158 is 8511661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8511661 = 251 ⋅33911.

It is a congruent 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 as a sum of consecutive naturals, namely, 415288 + ... + 415291.

It is an arithmetic number, because the mean of its divisors is an integer number (622935).

2^1661158 is an apocalyptic number.

1661158 is a deficient number, since it is larger than the sum of its proper divisors (830582).

1661158 is an equidigital number, since it uses as much as digits as its factorization.

1661158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830581.

The product of its digits is 1440, while the sum is 28.

The square root of 1661158 is about 1288.8591854815. The cubic root of 1661158 is about 118.4323410404.

The spelling of 1661158 in words is "one million, six hundred sixty-one thousand, one hundred fifty-eight".