20715747840 has 320 divisors, whose sum is σ = 74298280320. Its totient is φ = 5470617600.

The previous prime is 20715747797. The next prime is 20715747853. The reversal of 20715747840 is 4874751702.

20715747840 is a `hidden beast` number, since 2 + 0 + 7 + 1 + 574 + 78 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7394440 + ... + 7397240.

It is an arithmetic number, because the mean of its divisors is an integer number (232182126).

Almost surely, 2^20715747840 is an apocalyptic number.

20715747840 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 20715747840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37149140160).

20715747840 is an abundant number, since it is smaller than the sum of its proper divisors (53582532480).

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

20715747840 is a wasteful number, since it uses less digits than its factorization.

20715747840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2940 (or 2918 counting only the distinct ones).

The product of its (nonzero) digits is 439040, while the sum is 45.

The spelling of 20715747840 in words is "twenty billion, seven hundred fifteen million, seven hundred forty-seven thousand, eight hundred forty".