20611601 has 2 divisors, whose sum is σ = 20611602. Its totient is φ = 20611600.

The previous prime is 20611597. The next prime is 20611609. The reversal of 20611601 is 10611602.

It is a happy number.

It is a Cunningham number, because it is equal to 4540²+1.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 1 = 4540^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 20611601 - 2² = 20611597 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20611601.

It is not a weakly prime, because it can be changed into another prime (20611609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10305800 + 10305801.

It is an arithmetic number, because the mean of its divisors is an integer number (10305801).

Almost surely, 2^20611601 is an apocalyptic number.

It is an amenable number.

20611601 is a deficient number, since it is larger than the sum of its proper divisors (1).

20611601 is an equidigital number, since it uses as much as digits as its factorization.

20611601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 20611601 is about 4540.0001101322. Note that the first 3 decimals coincide. The cubic root of 20611601 is about 274.1809281524.

Subtracting from 20611601 its reverse (10611602), we obtain a palindrome (9999999).

It can be divided in two parts, 20611 and 601, that added together give a palindrome (21212).

The spelling of 20611601 in words is "twenty million, six hundred eleven thousand, six hundred one".