1665338840 has 32 divisors (see below), whose sum is σ = 4087650960. Its totient is φ = 605577600.

The previous prime is 1665338839. The next prime is 1665338903. The reversal of 1665338840 is 488335661.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 1665338791 and 1665338800.

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, 1891991 + ... + 1892870.

Almost surely, 2^1665338840 is an apocalyptic number.

1665338840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1665338840 is an abundant number, since it is smaller than the sum of its proper divisors (2422312120).

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

1665338840 is a wasteful number, since it uses less digits than its factorization.

1665338840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3784883 (or 3784879 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 44.

The square root of 1665338840 is about 40808.5633170294. The cubic root of 1665338840 is about 1185.3161553244.

The spelling of 1665338840 in words is "one billion, six hundred sixty-five million, three hundred thirty-eight thousand, eight hundred forty".