1640646 has 48 divisors (see below), whose sum is σ = 4212000. Its totient is φ = 451584.

The previous prime is 1640641. The next prime is 1640657. The reversal of 1640646 is 6460461.

1640646 is a `hidden beast` number, since 16 + 4 + 0 + 646 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3430 + ... + 3878.

It is an arithmetic number, because the mean of its divisors is an integer number (87750).

2^1640646 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2106000).

1640646 is an abundant number, since it is smaller than the sum of its proper divisors (2571354).

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

1640646 is a wasteful number, since it uses less digits than its factorization.

1640646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 1640646 is about 1280.8770432793. The cubic root of 1640646 is about 117.9428527265.

The spelling of 1640646 in words is "one million, six hundred forty thousand, six hundred forty-six".