20564280 has 160 divisors (see below), whose sum is σ = 75533040. Its totient is φ = 4976640.

The previous prime is 20564279. The next prime is 20564281. The reversal of 20564280 is 8246502.

20564280 is a `hidden beast` number, since 20 + 564 + 2 + 80 = 666.

It is an interprime number because it is at equal distance from previous prime (20564279) and next prime (20564281).

It is a super-2 number, since 2×20564280² = 845779223836800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564281) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 35352 + ... + 35928.

Almost surely, 2^20564280 is an apocalyptic number.

20564280 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 20564280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37766520).

20564280 is an abundant number, since it is smaller than the sum of its proper divisors (54968760).

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

20564280 is a wasteful number, since it uses less digits than its factorization.

20564280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611 (or 598 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20564280 is about 4534.7855517102. The cubic root of 20564280 is about 273.9709419164.

It can be divided in two parts, 2056 and 4280, that added together give a palindrome (6336).

The spelling of 20564280 in words is "twenty million, five hundred sixty-four thousand, two hundred eighty".