1666810440 has 128 divisors (see below), whose sum is σ = 5565024000. Its totient is φ = 443764224.

The previous prime is 1666810381. The next prime is 1666810459. The reversal of 1666810440 is 440186661.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1666810395 and 1666810404.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1218637 + ... + 1220003.

It is an arithmetic number, because the mean of its divisors is an integer number (43476750).

Almost surely, 2^1666810440 is an apocalyptic number.

1666810440 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 1666810440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2782512000).

1666810440 is an abundant number, since it is smaller than the sum of its proper divisors (3898213560).

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

1666810440 is a wasteful number, since it uses less digits than its factorization.

1666810440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2516 (or 2506 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 1666810440 is about 40826.5898649397. The cubic root of 1666810440 is about 1185.6651929435.

The spelling of 1666810440 in words is "one billion, six hundred sixty-six million, eight hundred ten thousand, four hundred forty".