20561104 has 10 divisors (see below), whose sum is σ = 39837170. Its totient is φ = 10280544.

The previous prime is 20561083. The next prime is 20561111. The reversal of 20561104 is 40116502.

It can be written as a sum of positive squares in only one way, i.e., 10575504 + 9985600 = 3252^2 + 3160^2 .

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 642519 + ... + 642550.

It is an arithmetic number, because the mean of its divisors is an integer number (3983717).

Almost surely, 2^20561104 is an apocalyptic number.

It is an amenable number.

20561104 is a deficient number, since it is larger than the sum of its proper divisors (19276066).

20561104 is a wasteful number, since it uses less digits than its factorization.

20561104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1285077 (or 1285071 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 20561104 is about 4534.4353562489. The cubic root of 20561104 is about 273.9568369326.

Adding to 20561104 its reverse (40116502), we get a palindrome (60677606).

It can be divided in two parts, 2056 and 1104, that added together give a triangular number (3160 = T₇₉).

The spelling of 20561104 in words is "twenty million, five hundred sixty-one thousand, one hundred four".