19980644 has 24 divisors (see below), whose sum is σ = 37322208. Its totient is φ = 9326720.

The previous prime is 19980643. The next prime is 19980659. The reversal of 19980644 is 44608991.

It is a super-2 number, since 2×19980644² = 798452269309472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19980641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7787 + ... + 10029.

It is an arithmetic number, because the mean of its divisors is an integer number (1555092).

Almost surely, 2^19980644 is an apocalyptic number.

It is an amenable number.

19980644 is a deficient number, since it is larger than the sum of its proper divisors (17341564).

19980644 is a wasteful number, since it uses less digits than its factorization.

19980644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2395 (or 2393 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 19980644 is about 4469.9713645615. The cubic root of 19980644 is about 271.3541662828.

The spelling of 19980644 in words is "nineteen million, nine hundred eighty thousand, six hundred forty-four".