1661120 has 56 divisors (see below), whose sum is σ = 4114800. Its totient is φ = 637952.

The previous prime is 1661117. The next prime is 1661123. The reversal of 1661120 is 211661.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1661117) and next prime (1661123).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1661123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9191 + ... + 9369.

2^1661120 is an apocalyptic number.

1661120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2057400).

1661120 is an abundant number, since it is smaller than the sum of its proper divisors (2453680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661120 is a wasteful number, since it uses less digits than its factorization.

1661120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1661120 is about 1288.8444436781. The cubic root of 1661120 is about 118.4314379629.

Adding to 1661120 its reverse (211661), we get a palindrome (1872781).

The spelling of 1661120 in words is "one million, six hundred sixty-one thousand, one hundred twenty".