19665940 has 48 divisors (see below), whose sum is σ = 49980672. Its totient is φ = 6345216.

The previous prime is 19665929. The next prime is 19665941. The reversal of 19665940 is 4956691.

It is a junction number, because it is equal to n+sod(n) for n = 19665893 and 19665902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19665941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1752 + ... + 6511.

It is an arithmetic number, because the mean of its divisors is an integer number (1041264).

Almost surely, 2^19665940 is an apocalyptic number.

19665940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19665940 is an abundant number, since it is smaller than the sum of its proper divisors (30314732).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19665940 is a wasteful number, since it uses less digits than its factorization.

19665940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8296 (or 8294 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 40.

The square root of 19665940 is about 4434.6296350428. The cubic root of 19665940 is about 269.9219710506.

The spelling of 19665940 in words is "nineteen million, six hundred sixty-five thousand, nine hundred forty".