1997644 has 24 divisors (see below), whose sum is σ = 3866688. Its totient is φ = 895440.

The previous prime is 1997617. The next prime is 1997647. The reversal of 1997644 is 4467991.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1997597 and 1997606.

It is not an unprimeable number, because it can be changed into a prime (1997647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3379 + ... + 3925.

It is an arithmetic number, because the mean of its divisors is an integer number (161112).

2^1997644 is an apocalyptic number.

It is an amenable number.

1997644 is a deficient number, since it is larger than the sum of its proper divisors (1869044).

1997644 is a wasteful number, since it uses less digits than its factorization.

1997644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645 (or 643 counting only the distinct ones).

The product of its digits is 54432, while the sum is 40.

The square root of 1997644 is about 1413.3803451301. The cubic root of 1997644 is about 125.9426126505.

The spelling of 1997644 in words is "one million, nine hundred ninety-seven thousand, six hundred forty-four".