19531644816 has 20 divisors (see below), whose sum is σ = 50456749232. Its totient is φ = 6510548256.

The previous prime is 19531644799. The next prime is 19531644823. The reversal of 19531644816 is 61844613591.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48), and also a Moran number because the ratio is a prime number: 406909267 = 19531644816 / (1 + 9 + 5 + 3 + 1 + 6 + 4 + 4 + 8 + 1 + 6).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203454586 + ... + 203454681.

Almost surely, 2^19531644816 is an apocalyptic number.

19531644816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19531644816 is an abundant number, since it is smaller than the sum of its proper divisors (30925104416).

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

19531644816 is a wasteful number, since it uses less digits than its factorization.

19531644816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406909278 (or 406909272 counting only the distinct ones).

The product of its digits is 622080, while the sum is 48.

The spelling of 19531644816 in words is "nineteen billion, five hundred thirty-one million, six hundred forty-four thousand, eight hundred sixteen".