20709647388 has 72 divisors (see below), whose sum is σ = 54268905600. Its totient is φ = 6651098496.

The previous prime is 20709647383. The next prime is 20709647393. The reversal of 20709647388 is 88374690702.

20709647388 is a `hidden beast` number, since 2 + 0 + 7 + 0 + 96 + 473 + 88 = 666.

It is an interprime number because it is at equal distance from previous prime (20709647383) and next prime (20709647393).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20709647381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 479370 + ... + 520782.

It is an arithmetic number, because the mean of its divisors is an integer number (753734800).

Almost surely, 2^20709647388 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20709647388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27134452800).

20709647388 is an abundant number, since it is smaller than the sum of its proper divisors (33559258212).

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

20709647388 is a wasteful number, since it uses less digits than its factorization.

20709647388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41931 (or 41926 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 20709647388 in words is "twenty billion, seven hundred nine million, six hundred forty-seven thousand, three hundred eighty-eight".