19491948816 has 20 divisors (see below), whose sum is σ = 50354201232. Its totient is φ = 6497316256.

The previous prime is 19491948809. The next prime is 19491948841. The reversal of 19491948816 is 61884919491.

It is a self number, because there is not a number n which added to its sum of digits gives 19491948816.

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, 203041086 + ... + 203041181.

Almost surely, 2^19491948816 is an apocalyptic number.

19491948816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19491948816 is an abundant number, since it is smaller than the sum of its proper divisors (30862252416).

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

19491948816 is a wasteful number, since it uses less digits than its factorization.

19491948816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406082278 (or 406082272 counting only the distinct ones).

The product of its digits is 4478976, while the sum is 60.

The spelling of 19491948816 in words is "nineteen billion, four hundred ninety-one million, nine hundred forty-eight thousand, eight hundred sixteen".