20564839280 has 20 divisors (see below), whose sum is σ = 47813251512. Its totient is φ = 8225935680.

The previous prime is 20564839249. The next prime is 20564839283. The reversal of 20564839280 is 8293846502.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×20564839280² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (47) 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 (20564839283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128530166 + ... + 128530325.

Almost surely, 2^20564839280 is an apocalyptic number.

20564839280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20564839280 is an abundant number, since it is smaller than the sum of its proper divisors (27248412232).

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

20564839280 is a wasteful number, since it uses less digits than its factorization.

20564839280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257060504 (or 257060498 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 47.

The spelling of 20564839280 in words is "twenty billion, five hundred sixty-four million, eight hundred thirty-nine thousand, two hundred eighty".