19840949537838 has 128 divisors (see below), whose sum is σ = 48683616952320. Its totient is φ = 5304534238080.

The previous prime is 19840949537833. The next prime is 19840949537839. The reversal of 19840949537838 is 83873594904891.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19840949537833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 25327593 + ... + 26099211.

It is an arithmetic number, because the mean of its divisors is an integer number (380340757440).

Almost surely, 2^{19840949537838} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19840949537838, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24341808476160).

19840949537838 is an abundant number, since it is smaller than the sum of its proper divisors (28842667414482).

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

19840949537838 is a wasteful number, since it uses less digits than its factorization.

19840949537838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 772974.

The product of its (nonzero) digits is 1881169920, while the sum is 78.

The spelling of 19840949537838 in words is "nineteen trillion, eight hundred forty billion, nine hundred forty-nine million, five hundred thirty-seven thousand, eight hundred thirty-eight".