20564251008 has 384 divisors, whose sum is σ = 68605665120. Its totient is φ = 5421072384.

The previous prime is 20564250947. The next prime is 20564251013. The reversal of 20564251008 is 80015246502.

It is a tau number, because it is divible by the number of its divisors (384).

It is a self number, because there is not a number n which added to its sum of digits gives 20564251008.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16952610 + ... + 16953822.

Almost surely, 2^20564251008 is an apocalyptic number.

20564251008 is a gapful number since it is divisible by the number (28) 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 20564251008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34302832560).

20564251008 is an abundant number, since it is smaller than the sum of its proper divisors (48041414112).

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

20564251008 is a wasteful number, since it uses less digits than its factorization.

20564251008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314 (or 1295 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 33.

The spelling of 20564251008 in words is "twenty billion, five hundred sixty-four million, two hundred fifty-one thousand, eight".