1665544540 has 96 divisors (see below), whose sum is σ = 4022161920. Its totient is φ = 573408000.

The previous prime is 1665544537. The next prime is 1665544561. The reversal of 1665544540 is 454455661.

It is a super-2 number, since 2×1665544540² = 5548077229447623200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1665544493 and 1665544502.

It is a congruent number.

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, 509431 + ... + 512689.

It is an arithmetic number, because the mean of its divisors is an integer number (41897520).

Almost surely, 2^1665544540 is an apocalyptic number.

1665544540 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 1665544540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2011080960).

1665544540 is an abundant number, since it is smaller than the sum of its proper divisors (2356617380).

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

1665544540 is a wasteful number, since it uses less digits than its factorization.

1665544540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3403 (or 3401 counting only the distinct ones).

The product of its (nonzero) digits is 288000, while the sum is 40.

The square root of 1665544540 is about 40811.0835435669. The cubic root of 1665544540 is about 1185.3649561028.

It can be divided in two parts, 16 and 65544540, that added together give a palindrome (65544556).

The spelling of 1665544540 in words is "one billion, six hundred sixty-five million, five hundred forty-four thousand, five hundred forty".