19866633816 has 64 divisors (see below), whose sum is σ = 49869198720. Its totient is φ = 6595258880.

The previous prime is 19866633767. The next prime is 19866633817. The reversal of 19866633816 is 61833666891.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19866633817) 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, 6986491 + ... + 6989333.

It is an arithmetic number, because the mean of its divisors is an integer number (779206230).

Almost surely, 2^19866633816 is an apocalyptic number.

It is an amenable number.

19866633816 is an abundant number, since it is smaller than the sum of its proper divisors (30002564904).

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

19866633816 is a wasteful number, since it uses less digits than its factorization.

19866633816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3936 (or 3932 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 57.

The spelling of 19866633816 in words is "nineteen billion, eight hundred sixty-six million, six hundred thirty-three thousand, eight hundred sixteen".