20477 has 2 divisors, whose sum is σ = 20478. Its totient is φ = 20476.

The previous prime is 20443. The next prime is 20479. The reversal of 20477 is 77402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19321 + 1156 = 139^2 + 34^2 .

It is a cyclic number.

It is not a de Polignac number, because 20477 - 2¹² = 16381 is a prime.

Together with 20479, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 6.

It is a nialpdrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20477.

It is not a weakly prime, because it can be changed into another prime (20479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10238 + 10239.

It is an arithmetic number, because the mean of its divisors is an integer number (10239).

2²⁰⁴⁷⁷ is an apocalyptic number.

It is an amenable number.

20477 is a deficient number, since it is larger than the sum of its proper divisors (1).

20477 is an equidigital number, since it uses as much as digits as its factorization.

20477 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 392, while the sum is 20.

The square root of 20477 is about 143.0978686075. The cubic root of 20477 is about 27.3582791629.

Adding to 20477 its reverse (77402), we get a palindrome (97879).

The spelling of 20477 in words is "twenty thousand, four hundred seventy-seven", and thus it is an iban number.