20564740 has 24 divisors (see below), whose sum is σ = 49355712. Its totient is φ = 7050720.

The previous prime is 20564717. The next prime is 20564743. The reversal of 20564740 is 4746502.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 20564699 and 20564708.

It is not an unprimeable number, because it can be changed into a prime (20564743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73306 + ... + 73585.

It is an arithmetic number, because the mean of its divisors is an integer number (2056488).

Almost surely, 2^20564740 is an apocalyptic number.

20564740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20564740 is an abundant number, since it is smaller than the sum of its proper divisors (28790972).

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

20564740 is a wasteful number, since it uses less digits than its factorization.

20564740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146907 (or 146905 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 20564740 is about 4534.8362704733. The cubic root of 20564740 is about 273.9729847093.

The spelling of 20564740 in words is "twenty million, five hundred sixty-four thousand, seven hundred forty".