20055661 has 2 divisors, whose sum is σ = 20055662. Its totient is φ = 20055660.

The previous prime is 20055649. The next prime is 20055709. The reversal of 20055661 is 16655002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17556100 + 2499561 = 4190^2 + 1581^2 .

It is a cyclic number.

It is not a de Polignac number, because 20055661 - 2¹¹ = 20053613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20055611) 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 as a sum of consecutive naturals, namely, 10027830 + 10027831.

It is an arithmetic number, because the mean of its divisors is an integer number (10027831).

Almost surely, 2^20055661 is an apocalyptic number.

It is an amenable number.

20055661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20055661 is an equidigital number, since it uses as much as digits as its factorization.

20055661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 20055661 is about 4478.3547202070. The cubic root of 20055661 is about 271.6933404165.

The spelling of 20055661 in words is "twenty million, fifty-five thousand, six hundred sixty-one".