20564737 has 4 divisors (see below), whose sum is σ = 21458880. Its totient is φ = 19670596.

The previous prime is 20564717. The next prime is 20564743. The reversal of 20564737 is 73746502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 73746502 = 2 ⋅36873251.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20564737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20564717) 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 3 ways as a sum of consecutive naturals, for example, 447037 + ... + 447082.

It is an arithmetic number, because the mean of its divisors is an integer number (5364720).

Almost surely, 2^20564737 is an apocalyptic number.

It is an amenable number.

20564737 is a deficient number, since it is larger than the sum of its proper divisors (894143).

20564737 is an equidigital number, since it uses as much as digits as its factorization.

20564737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 894142.

The product of its (nonzero) digits is 35280, while the sum is 34.

The square root of 20564737 is about 4534.8359397006. The cubic root of 20564737 is about 273.9729713868.

The spelling of 20564737 in words is "twenty million, five hundred sixty-four thousand, seven hundred thirty-seven".