20591619840 has 432 divisors, whose sum is σ = 79550190720. Its totient is φ = 4874526720.

The previous prime is 20591619823. The next prime is 20591619847. The reversal of 20591619840 is 4891619502.

20591619840 is a `hidden beast` number, since 2 + 0 + 591 + 6 + 19 + 8 + 40 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20591619847) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5447071 + ... + 5450849.

It is an arithmetic number, because the mean of its divisors is an integer number (184143960).

Almost surely, 2^20591619840 is an apocalyptic number.

20591619840 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 20591619840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39775095360).

20591619840 is an abundant number, since it is smaller than the sum of its proper divisors (58958570880).

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

20591619840 is a wasteful number, since it uses less digits than its factorization.

20591619840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3860 (or 3843 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 20591619840 in words is "twenty billion, five hundred ninety-one million, six hundred nineteen thousand, eight hundred forty".