1668403440 has 640 divisors, whose sum is σ = 6788136960. Its totient is φ = 372556800.

The previous prime is 1668403439. The next prime is 1668403453. The reversal of 1668403440 is 443048661.

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 = 1668403395 and 1668403404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 23498605 + ... + 23498675.

It is an arithmetic number, because the mean of its divisors is an integer number (10606464).

Almost surely, 2^1668403440 is an apocalyptic number.

1668403440 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 1668403440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3394068480).

1668403440 is an abundant number, since it is smaller than the sum of its proper divisors (5119733520).

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

1668403440 is a wasteful number, since it uses less digits than its factorization.

1668403440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 1668403440 is about 40846.0945501525. The cubic root of 1668403440 is about 1186.0427930229.

The spelling of 1668403440 in words is "one billion, six hundred sixty-eight million, four hundred three thousand, four hundred forty".