20505497 has 2 divisors, whose sum is σ = 20505498. Its totient is φ = 20505496.

The previous prime is 20505493. The next prime is 20505571. The reversal of 20505497 is 79450502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19456921 + 1048576 = 4411^2 + 1024^2 .

It is a cyclic number.

It is not a de Polignac number, because 20505497 - 2² = 20505493 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20505491) 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, 10252748 + 10252749.

It is an arithmetic number, because the mean of its divisors is an integer number (10252749).

Almost surely, 2^20505497 is an apocalyptic number.

It is an amenable number.

20505497 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505497 is an equidigital number, since it uses as much as digits as its factorization.

20505497 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 20505497 is about 4528.2995704790. The cubic root of 20505497 is about 273.7096441140.

Adding to 20505497 its reverse (79450502), we get a palindrome (99955999).

The spelling of 20505497 in words is "twenty million, five hundred five thousand, four hundred ninety-seven".