1643648 has 16 divisors (see below), whose sum is σ = 3274710. Its totient is φ = 821760.

The previous prime is 1643641. The next prime is 1643659. The reversal of 1643648 is 8463461.

It can be written as a sum of positive squares in only one way, i.e., 1420864 + 222784 = 1192^2 + 472^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a super-3 number, since 3×1643648³ = 13321333517504741376, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (1643641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6293 + ... + 6548.

2^1643648 is an apocalyptic number.

It is an amenable number.

1643648 is a deficient number, since it is larger than the sum of its proper divisors (1631062).

1643648 is an equidigital number, since it uses as much as digits as its factorization.

1643648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12855 (or 12843 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 1643648 is about 1282.0483610223. The cubic root of 1643648 is about 118.0147448777.

The spelling of 1643648 in words is "one million, six hundred forty-three thousand, six hundred forty-eight".