20655749 has 2 divisors, whose sum is σ = 20655750. Its totient is φ = 20655748.

The previous prime is 20655737. The next prime is 20655751. The reversal of 20655749 is 94755602.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20638849 + 16900 = 4543^2 + 130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20655749 is a prime.

Together with 20655751, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20655049) 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 as a sum of consecutive naturals, namely, 10327874 + 10327875.

It is an arithmetic number, because the mean of its divisors is an integer number (10327875).

Almost surely, 2^20655749 is an apocalyptic number.

It is an amenable number.

20655749 is a deficient number, since it is larger than the sum of its proper divisors (1).

20655749 is an equidigital number, since it uses as much as digits as its factorization.

20655749 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 20655749 is about 4544.8596237948. The cubic root of 20655749 is about 274.3765446509.

It can be divided in two parts, 206 and 55749, that added together give a palindrome (55955).

The spelling of 20655749 in words is "twenty million, six hundred fifty-five thousand, seven hundred forty-nine".