1665648 has 60 divisors (see below), whose sum is σ = 4787640. Its totient is φ = 540288.

The previous prime is 1665647. The next prime is 1665649. The reversal of 1665648 is 8465661.

1665648 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 648 = 666.

It is an interprime number because it is at equal distance from previous prime (1665647) and next prime (1665649).

It is a super-3 number, since 3×1665648³ = 13863437784277733376, which contains 333 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665647) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6058 + ... + 6326.

It is an arithmetic number, because the mean of its divisors is an integer number (79794).

2^1665648 is an apocalyptic number.

1665648 is a gapful number since it is divisible by the number (18) 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 1665648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2393820).

1665648 is an abundant number, since it is smaller than the sum of its proper divisors (3121992).

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

1665648 is a wasteful number, since it uses less digits than its factorization.

1665648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 317 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 1665648 is about 1290.5998605300. The cubic root of 1665648 is about 118.5389499691.

The spelling of 1665648 in words is "one million, six hundred sixty-five thousand, six hundred forty-eight".