19491678444 has 36 divisors (see below), whose sum is σ = 52905985944. Its totient is φ = 5569050816.

The previous prime is 19491678439. The next prime is 19491678449. The reversal of 19491678444 is 44487619491.

It is an interprime number because it is at equal distance from previous prime (19491678439) and next prime (19491678449).

It is a super-2 number, since 2×19491678444² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19491678449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16573969 + ... + 16575144.

Almost surely, 2^19491678444 is an apocalyptic number.

19491678444 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

19491678444 is an abundant number, since it is smaller than the sum of its proper divisors (33414307500).

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

19491678444 is a wasteful number, since it uses less digits than its factorization.

19491678444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33149134 (or 33149125 counting only the distinct ones).

The product of its digits is 6967296, while the sum is 57.

The spelling of 19491678444 in words is "nineteen billion, four hundred ninety-one million, six hundred seventy-eight thousand, four hundred forty-four".