20565393408 has 408 divisors, whose sum is σ = 72137284128. Its totient is φ = 5511315456.

The previous prime is 20565393389. The next prime is 20565393421. The reversal of 20565393408 is 80439356502.

20565393408 is a `hidden beast` number, since 20 + 56 + 539 + 3 + 40 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (408).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70188910 + ... + 70189202.

Almost surely, 2^20565393408 is an apocalyptic number.

20565393408 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 20565393408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36068642064).

20565393408 is an abundant number, since it is smaller than the sum of its proper divisors (51571890720).

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

20565393408 is an equidigital number, since it uses as much as digits as its factorization.

20565393408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 20565393408 in words is "twenty billion, five hundred sixty-five million, three hundred ninety-three thousand, four hundred eight".