1664990 has 16 divisors (see below), whose sum is σ = 3017952. Its totient is φ = 661344.

The previous prime is 1664987. The next prime is 1665007. The reversal of 1664990 is 994661.

It is an Ulam number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1664990.

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, 1172 + ... + 2168.

It is an arithmetic number, because the mean of its divisors is an integer number (188622).

2^1664990 is an apocalyptic number.

1664990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1664990 is a deficient number, since it is larger than the sum of its proper divisors (1352962).

1664990 is a wasteful number, since it uses less digits than its factorization.

1664990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1171.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 1664990 is about 1290.3449151293. The cubic root of 1664990 is about 118.5233386470.

The spelling of 1664990 in words is "one million, six hundred sixty-four thousand, nine hundred ninety".