19910499840 has 1600 divisors, whose sum is σ = 94114690560. Its totient is φ = 3901685760.

The previous prime is 19910499839. The next prime is 19910499853. The reversal of 19910499840 is 4899401991.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 463034859 + ... + 463034901.

Almost surely, 2^19910499840 is an apocalyptic number.

19910499840 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 19910499840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47057345280).

19910499840 is an abundant number, since it is smaller than the sum of its proper divisors (74204190720).

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

19910499840 is a wasteful number, since it uses less digits than its factorization.

19910499840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 54.

The spelling of 19910499840 in words is "nineteen billion, nine hundred ten million, four hundred ninety-nine thousand, eight hundred forty".