20504681 has 2 divisors, whose sum is σ = 20504682. Its totient is φ = 20504680.

The previous prime is 20504677. The next prime is 20504713. The reversal of 20504681 is 18640502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 434281 = 4480^2 + 659^2 .

It is a cyclic number.

It is not a de Polignac number, because 20504681 - 2² = 20504677 is a prime.

It is a super-2 number, since 2×20504681² = 840883885823522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20504681.

It is not a weakly prime, because it can be changed into another prime (20504611) 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, 10252340 + 10252341.

It is an arithmetic number, because the mean of its divisors is an integer number (10252341).

Almost surely, 2^20504681 is an apocalyptic number.

It is an amenable number.

20504681 is a deficient number, since it is larger than the sum of its proper divisors (1).

20504681 is an equidigital number, since it uses as much as digits as its factorization.

20504681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20504681 is about 4528.2094695365. The cubic root of 20504681 is about 273.7060133797.

The spelling of 20504681 in words is "twenty million, five hundred four thousand, six hundred eighty-one".