20819313840 has 640 divisors, whose sum is σ = 78804956160. Its totient is φ = 4490919936.

The previous prime is 20819313833. The next prime is 20819313841. The reversal of 20819313840 is 4831391802.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (20819313841) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 73566339 + ... + 73566621.

It is an arithmetic number, because the mean of its divisors is an integer number (123132744).

Almost surely, 2^20819313840 is an apocalyptic number.

20819313840 is a gapful number since it is divisible by the number (20) 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 20819313840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39402478080).

20819313840 is an abundant number, since it is smaller than the sum of its proper divisors (57985642320).

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

20819313840 is a wasteful number, since it uses less digits than its factorization.

20819313840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The spelling of 20819313840 in words is "twenty billion, eight hundred nineteen million, three hundred thirteen thousand, eight hundred forty".