20335561 has 4 divisors (see below), whose sum is σ = 20482000. Its totient is φ = 20189124.

The previous prime is 20335559. The next prime is 20335571. The reversal of 20335561 is 16553302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20335561 - 2¹ = 20335559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20335501) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 73011 + ... + 73288.

It is an arithmetic number, because the mean of its divisors is an integer number (5120500).

Almost surely, 2^20335561 is an apocalyptic number.

It is an amenable number.

20335561 is a deficient number, since it is larger than the sum of its proper divisors (146439).

20335561 is a wasteful number, since it uses less digits than its factorization.

20335561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146438.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 20335561 is about 4509.4967568455. The cubic root of 20335561 is about 272.9514375552.

Adding to 20335561 its reverse (16553302), we get a palindrome (36888863).

The spelling of 20335561 in words is "twenty million, three hundred thirty-five thousand, five hundred sixty-one".