20809061 has 16 divisors (see below), whose sum is σ = 26001024. Its totient is φ = 16213824.

The previous prime is 20809057. The next prime is 20809073. The reversal of 20809061 is 16090802.

It is a cyclic number.

It is not a de Polignac number, because 20809061 - 2² = 20809057 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20809061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20809051) 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 15 ways as a sum of consecutive naturals, for example, 4391 + ... + 7803.

It is an arithmetic number, because the mean of its divisors is an integer number (1625064).

Almost surely, 2^20809061 is an apocalyptic number.

It is an amenable number.

20809061 is a deficient number, since it is larger than the sum of its proper divisors (5191963).

20809061 is a wasteful number, since it uses less digits than its factorization.

20809061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3500.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 20809061 is about 4561.6949700742. The cubic root of 20809061 is about 275.0537019091.

Adding to 20809061 its reverse (16090802), we get a palindrome (36899863).

The spelling of 20809061 in words is "twenty million, eight hundred nine thousand, sixty-one".