20563621 has 8 divisors (see below), whose sum is σ = 22426880. Its totient is φ = 18740592.

The previous prime is 20563607. The next prime is 20563637. The reversal of 20563621 is 12636502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20563621 - 2⁷ = 20563493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20563651) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 8985 + ... + 11038.

It is an arithmetic number, because the mean of its divisors is an integer number (2803360).

Almost surely, 2^20563621 is an apocalyptic number.

It is an amenable number.

20563621 is a deficient number, since it is larger than the sum of its proper divisors (1863259).

20563621 is a wasteful number, since it uses less digits than its factorization.

20563621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20115.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20563621 is about 4534.7128905808. The cubic root of 20563621 is about 273.9680153405.

The spelling of 20563621 in words is "twenty million, five hundred sixty-three thousand, six hundred twenty-one".