19979539800 has 192 divisors, whose sum is σ = 67835836800. Its totient is φ = 4824268800.

The previous prime is 19979539759. The next prime is 19979539837. The reversal of 19979539800 is 893597991.

It is a Cunningham number, because it is equal to 141349²-1.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1690311 + ... + 1702089.

It is an arithmetic number, because the mean of its divisors is an integer number (353311650).

Almost surely, 2^19979539800 is an apocalyptic number.

19979539800 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 19979539800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33917918400).

19979539800 is an abundant number, since it is smaller than the sum of its proper divisors (47856297000).

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

19979539800 is a wasteful number, since it uses less digits than its factorization.

19979539800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12066 (or 12057 counting only the distinct ones).

The product of its (nonzero) digits is 5511240, while the sum is 60.

The spelling of 19979539800 in words is "nineteen billion, nine hundred seventy-nine million, five hundred thirty-nine thousand, eight hundred".