20569904640 has 800 divisors, whose sum is σ = 81280869120. Its totient is φ = 4948770816.

The previous prime is 20569904633. The next prime is 20569904671. The reversal of 20569904640 is 4640996502.

20569904640 is a `hidden beast` number, since 2 + 0 + 569 + 9 + 0 + 46 + 40 = 666.

It is a super-3 number, since 3×20569904640³ (a number of 32 digits) contains 333 as substring.

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 polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 90616207 + ... + 90616433.

Almost surely, 2^20569904640 is an apocalyptic number.

20569904640 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 20569904640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40640434560).

20569904640 is an abundant number, since it is smaller than the sum of its proper divisors (60710964480).

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

20569904640 is a wasteful number, since it uses less digits than its factorization.

20569904640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 20569904640 in words is "twenty billion, five hundred sixty-nine million, nine hundred four thousand, six hundred forty".