1999172891448 has 96 divisors (see below), whose sum is σ = 5618982096000. Its totient is φ = 665913724128.

The previous prime is 1999172891447. The next prime is 1999172891459. The reversal of 1999172891448 is 8441982719991.

1999172891448 is a `hidden beast` number, since 1 + 9 + 9 + 9 + 172 + 8 + 9 + 1 + 448 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999172891447) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2352115 + ... + 3087197.

It is an arithmetic number, because the mean of its divisors is an integer number (58531063500).

Almost surely, 2^{1999172891448} is an apocalyptic number.

1999172891448 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1999172891448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2809491048000).

1999172891448 is an abundant number, since it is smaller than the sum of its proper divisors (3619809204552).

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

1999172891448 is a wasteful number, since it uses less digits than its factorization.

1999172891448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 736503 (or 736487 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 72.

The spelling of 1999172891448 in words is "one trillion, nine hundred ninety-nine billion, one hundred seventy-two million, eight hundred ninety-one thousand, four hundred forty-eight".