19980645 has 32 divisors (see below), whose sum is σ = 32970240. Its totient is φ = 10328640.

The previous prime is 19980643. The next prime is 19980659. The reversal of 19980645 is 54608991.

It is not a de Polignac number, because 19980645 - 2¹ = 19980643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19980597 and 19980606.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94590 + ... + 94800.

It is an arithmetic number, because the mean of its divisors is an integer number (1030320).

Almost surely, 2^19980645 is an apocalyptic number.

19980645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19980645 is a deficient number, since it is larger than the sum of its proper divisors (12989595).

19980645 is a wasteful number, since it uses less digits than its factorization.

19980645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 19980645 is about 4469.9714764191. The cubic root of 19980645 is about 271.3541708098.

The spelling of 19980645 in words is "nineteen million, nine hundred eighty thousand, six hundred forty-five".