20561144 has 16 divisors (see below), whose sum is σ = 38610000. Its totient is φ = 10265152.

The previous prime is 20561117. The next prime is 20561147. The reversal of 20561144 is 44116502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561147) 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, 5357 + ... + 8355.

It is an arithmetic number, because the mean of its divisors is an integer number (2413125).

Almost surely, 2^20561144 is an apocalyptic number.

It is an amenable number.

20561144 is a deficient number, since it is larger than the sum of its proper divisors (18048856).

20561144 is a wasteful number, since it uses less digits than its factorization.

20561144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3862 (or 3858 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 20561144 is about 4534.4397669392. The cubic root of 20561144 is about 273.9570145863.

Adding to 20561144 its reverse (44116502), we get a palindrome (64677646).

The spelling of 20561144 in words is "twenty million, five hundred sixty-one thousand, one hundred forty-four".