1661648 has 40 divisors (see below), whose sum is σ = 3515400. Its totient is φ = 757760.

The previous prime is 1661641. The next prime is 1661659. The reversal of 1661648 is 8461661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2704 + 1658944 = 52^2 + 1288^2 .

It is a super-2 number, since 2×1661648² = 5522148151808, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11078 + ... + 11226.

It is an arithmetic number, because the mean of its divisors is an integer number (87885).

2^1661648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1757700).

1661648 is an abundant number, since it is smaller than the sum of its proper divisors (1853752).

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

1661648 is a wasteful number, since it uses less digits than its factorization.

1661648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 209 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 1661648 is about 1289.0492620532. The cubic root of 1661648 is about 118.4439847536.

The spelling of 1661648 in words is "one million, six hundred sixty-one thousand, six hundred forty-eight".