19999660 has 12 divisors (see below), whose sum is σ = 41999328. Its totient is φ = 7999856.

The previous prime is 19999631. The next prime is 19999663. The reversal of 19999660 is 6699991.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (19999663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 499972 + ... + 500011.

It is an arithmetic number, because the mean of its divisors is an integer number (3499944).

Almost surely, 2^19999660 is an apocalyptic number.

19999660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19999660 is an abundant number, since it is smaller than the sum of its proper divisors (21999668).

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

19999660 is a wasteful number, since it uses less digits than its factorization.

19999660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999992 (or 999990 counting only the distinct ones).

The product of its (nonzero) digits is 236196, while the sum is 49.

The square root of 19999660 is about 4472.0979416824. The cubic root of 19999660 is about 271.4402234808.

The spelling of 19999660 in words is "nineteen million, nine hundred ninety-nine thousand, six hundred sixty".