1661845400 has 24 divisors (see below), whose sum is σ = 3863791020. Its totient is φ = 664738080.

The previous prime is 1661845357. The next prime is 1661845403. The reversal of 1661845400 is 45481661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661845403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4154414 + ... + 4154813.

Almost surely, 2^1661845400 is an apocalyptic number.

1661845400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661845400 is an abundant number, since it is smaller than the sum of its proper divisors (2201945620).

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

1661845400 is a wasteful number, since it uses less digits than its factorization.

1661845400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8309243 (or 8309234 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 1661845400 is about 40765.7380651939. The cubic root of 1661845400 is about 1184.4867485985.

The spelling of 1661845400 in words is "one billion, six hundred sixty-one million, eight hundred forty-five thousand, four hundred".