1657664 has 28 divisors (see below), whose sum is σ = 3352800. Its totient is φ = 812928.

The previous prime is 1657661. The next prime is 1657673. The reversal of 1657664 is 4667561.

Added to its reverse (4667561) it gives a square (6325225 = 2515²).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1657661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3557 + ... + 3995.

2^1657664 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 1657664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1676400).

1657664 is an abundant number, since it is smaller than the sum of its proper divisors (1695136).

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

1657664 is an equidigital number, since it uses as much as digits as its factorization.

1657664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510 (or 500 counting only the distinct ones).

The product of its digits is 30240, while the sum is 35.

The square root of 1657664 is about 1287.5030097052. The cubic root of 1657664 is about 118.3492477880.

Adding to 1657664 its reverse (4667561), we get a square (6325225 = 2515²).

The spelling of 1657664 in words is "one million, six hundred fifty-seven thousand, six hundred sixty-four".