1668444440 has 32 divisors (see below), whose sum is σ = 4042770480. Its totient is φ = 616040832.

The previous prime is 1668444431. The next prime is 1668444497. The reversal of 1668444440 is 444448661.

It is a super-3 number, since 3×1668444440³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1603754 + ... + 1604793.

Almost surely, 2^1668444440 is an apocalyptic number.

1668444440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1668444440 is an abundant number, since it is smaller than the sum of its proper divisors (2374326040).

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

1668444440 is a wasteful number, since it uses less digits than its factorization.

1668444440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3208571 (or 3208567 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 41.

The square root of 1668444440 is about 40846.5964310369. The cubic root of 1668444440 is about 1186.0525083701.

The spelling of 1668444440 in words is "one billion, six hundred sixty-eight million, four hundred forty-four thousand, four hundred forty".