20289561 has 8 divisors (see below), whose sum is σ = 27079680. Its totient is φ = 13512912.

The previous prime is 20289559. The next prime is 20289583. The reversal of 20289561 is 16598202.

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

It is not a de Polignac number, because 20289561 - 2¹ = 20289559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20289541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 936 + ... + 6438.

It is an arithmetic number, because the mean of its divisors is an integer number (3384960).

Almost surely, 2^20289561 is an apocalyptic number.

It is an amenable number.

20289561 is a deficient number, since it is larger than the sum of its proper divisors (6790119).

20289561 is a wasteful number, since it uses less digits than its factorization.

20289561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6735.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 20289561 is about 4504.3935218850. The cubic root of 20289561 is about 272.7454724925.

The spelling of 20289561 in words is "twenty million, two hundred eighty-nine thousand, five hundred sixty-one".