1664340 has 24 divisors (see below), whose sum is σ = 4660320. Its totient is φ = 443808.

The previous prime is 1664291. The next prime is 1664353. The reversal of 1664340 is 434661.

1664340 = T₄₂₁ + T₄₂₂ + ... + T₄₃₈.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1664340.

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, 13810 + ... + 13929.

It is an arithmetic number, because the mean of its divisors is an integer number (194180).

2^1664340 is an apocalyptic number.

1664340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664340 is an abundant number, since it is smaller than the sum of its proper divisors (2995980).

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

1664340 is a wasteful number, since it uses less digits than its factorization.

1664340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27751 (or 27749 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 1664340 is about 1290.0930199021. The cubic root of 1664340 is about 118.5079130894.

The spelling of 1664340 in words is "one million, six hundred sixty-four thousand, three hundred forty".