20814561 has 12 divisors (see below), whose sum is σ = 30705792. Its totient is φ = 13580856.

The previous prime is 20814559. The next prime is 20814581. The reversal of 20814561 is 16541802.

20814561 is a `hidden beast` number, since 20 + 81 + 4 + 561 = 666.

It is not a de Polignac number, because 20814561 - 2¹ = 20814559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20814581) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24181 + ... + 25026.

It is an arithmetic number, because the mean of its divisors is an integer number (2558816).

Almost surely, 2^20814561 is an apocalyptic number.

It is an amenable number.

20814561 is a deficient number, since it is larger than the sum of its proper divisors (9891231).

20814561 is a wasteful number, since it uses less digits than its factorization.

20814561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49260 (or 49257 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 20814561 is about 4562.2977763403. The cubic root of 20814561 is about 275.0779327334.

The spelling of 20814561 in words is "twenty million, eight hundred fourteen thousand, five hundred sixty-one".