19991629440 has 528 divisors, whose sum is σ = 74940729570. Its totient is φ = 5099314176.

The previous prime is 19991629429. The next prime is 19991629477. The reversal of 19991629440 is 4492619991.

19991629440 is a `hidden beast` number, since 1 + 9 + 9 + 9 + 1 + 629 + 4 + 4 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17992466496 + 1999162944 = 134136^2 + 44712^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 65 ways as a sum of consecutive naturals, for example, 869201269 + ... + 869201291.

Almost surely, 2^19991629440 is an apocalyptic number.

19991629440 is a gapful number since it is divisible by the number (10) 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 19991629440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37470364785).

19991629440 is an abundant number, since it is smaller than the sum of its proper divisors (54949100130).

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

19991629440 is an frugal number, since it uses more digits than its factorization.

19991629440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 33 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 54.

The spelling of 19991629440 in words is "nineteen billion, nine hundred ninety-one million, six hundred twenty-nine thousand, four hundred forty".