20564820 has 48 divisors (see below), whose sum is σ = 63981120. Its totient is φ = 5483808.

The previous prime is 20564807. The next prime is 20564833. The reversal of 20564820 is 2846502.

20564820 is a `hidden beast` number, since 20 + 564 + 82 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (20564807) and next prime (20564833).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18502 + ... + 19581.

It is an arithmetic number, because the mean of its divisors is an integer number (1332940).

Almost surely, 2^20564820 is an apocalyptic number.

20564820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20564820 is an abundant number, since it is smaller than the sum of its proper divisors (43416300).

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

20564820 is a wasteful number, since it uses less digits than its factorization.

20564820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38101 (or 38093 counting only the distinct ones).

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

The square root of 20564820 is about 4534.8450910698. The cubic root of 20564820 is about 273.9733399745.

It can be divided in two parts, 205 and 64820, that added together give a square (65025 = 255²).

The spelling of 20564820 in words is "twenty million, five hundred sixty-four thousand, eight hundred twenty".