1664644 has 12 divisors (see below), whose sum is σ = 2925468. Its totient is φ = 828800.

The previous prime is 1664633. The next prime is 1664651. The reversal of 1664644 is 4464661.

It can be written as a sum of positive squares in 2 ways, for example, as 921600 + 743044 = 960^2 + 862^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 384 + ... + 1864.

It is an arithmetic number, because the mean of its divisors is an integer number (243789).

2^1664644 is an apocalyptic number.

It is an amenable number.

1664644 is a deficient number, since it is larger than the sum of its proper divisors (1260824).

1664644 is a wasteful number, since it uses less digits than its factorization.

1664644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1764 counting only the distinct ones).

The product of its digits is 13824, while the sum is 31.

The square root of 1664644 is about 1290.2108354839. The cubic root of 1664644 is about 118.5151280039.

It can be divided in two parts, 166464 and 4, that multiplied together give a square (665856 = 816²).

The spelling of 1664644 in words is "one million, six hundred sixty-four thousand, six hundred forty-four".