1660640 has 48 divisors (see below), whose sum is σ = 4000752. Its totient is φ = 651264.

The previous prime is 1660609. The next prime is 1660661. The reversal of 1660640 is 460661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15467 + ... + 15573.

It is an arithmetic number, because the mean of its divisors is an integer number (83349).

2^1660640 is an apocalyptic number.

1660640 is a gapful number since it is divisible by the number (10) 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 1660640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2000376).

1660640 is an abundant number, since it is smaller than the sum of its proper divisors (2340112).

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

1660640 is a wasteful number, since it uses less digits than its factorization.

1660640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 1660640 is about 1288.6582169063. The cubic root of 1660640 is about 118.4200294822.

The spelling of 1660640 in words is "one million, six hundred sixty thousand, six hundred forty".