20947351680 has 640 divisors, whose sum is σ = 78453650880. Its totient is φ = 5321023488.

The previous prime is 20947351661. The next prime is 20947351699. The reversal of 20947351680 is 8615374902.

It is an interprime number because it is at equal distance from previous prime (20947351661) and next prime (20947351699).

It is a tau number, because it is divible by the number of its divisors (640).

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

It is a congruent number.

It is an unprimeable number.

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 79 ways as a sum of consecutive naturals, for example, 128511279 + ... + 128511441.

It is a 1-persistent number, because it is pandigital, but 2⋅20947351680 = 41894703360 is not.

Almost surely, 2^20947351680 is an apocalyptic number.

20947351680 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 20947351680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39226825440).

20947351680 is an abundant number, since it is smaller than the sum of its proper divisors (57506299200).

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

20947351680 is a wasteful number, since it uses less digits than its factorization.

20947351680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298 (or 277 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 20947351680 in words is "twenty billion, nine hundred forty-seven million, three hundred fifty-one thousand, six hundred eighty".