20561798 has 8 divisors (see below), whose sum is σ = 31032408. Its totient is φ = 10217664.

The previous prime is 20561797. The next prime is 20561809. The reversal of 20561798 is 89716502.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561797) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31211 + ... + 31862.

It is an arithmetic number, because the mean of its divisors is an integer number (3879051).

Almost surely, 2^20561798 is an apocalyptic number.

20561798 is a deficient number, since it is larger than the sum of its proper divisors (10470610).

20561798 is a wasteful number, since it uses less digits than its factorization.

20561798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63238.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 20561798 is about 4534.5118811180. The cubic root of 20561798 is about 273.9599191910.

The spelling of 20561798 in words is "twenty million, five hundred sixty-one thousand, seven hundred ninety-eight".