20388481 has 2 divisors, whose sum is σ = 20388482. Its totient is φ = 20388480.

The previous prime is 20388469. The next prime is 20388509. The reversal of 20388481 is 18488302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15366400 + 5022081 = 3920^2 + 2241^2 .

It is a cyclic number.

It is not a de Polignac number, because 20388481 - 2⁵ = 20388449 is a prime.

It is a super-2 number, since 2×20388481² = 831380314974722, which contains 22 as substring.

It is equal to p_1293694 and since 20388481 and 1293694 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20388451) 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, 10194240 + 10194241.

It is an arithmetic number, because the mean of its divisors is an integer number (10194241).

Almost surely, 2^20388481 is an apocalyptic number.

It is an amenable number.

20388481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20388481 is an equidigital number, since it uses as much as digits as its factorization.

20388481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 20388481 is about 4515.3605614613. The cubic root of 20388481 is about 273.1880030846.

The spelling of 20388481 in words is "twenty million, three hundred eighty-eight thousand, four hundred eighty-one".