19808979840 has 512 divisors, whose sum is σ = 76340880000. Its totient is φ = 4825350144.

The previous prime is 19808979797. The next prime is 19808979851. The reversal of 19808979840 is 4897980891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24485356 + ... + 24486164.

Almost surely, 2^19808979840 is an apocalyptic number.

19808979840 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 19808979840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38170440000).

19808979840 is an abundant number, since it is smaller than the sum of its proper divisors (56531900160).

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

19808979840 is a wasteful number, since it uses less digits than its factorization.

19808979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 959 (or 941 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 63.

The spelling of 19808979840 in words is "nineteen billion, eight hundred eight million, nine hundred seventy-nine thousand, eight hundred forty".