20608681 has 2 divisors, whose sum is σ = 20608682. Its totient is φ = 20608680.

The previous prime is 20608661. The next prime is 20608723. The reversal of 20608681 is 18680602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16941456 + 3667225 = 4116^2 + 1915^2 .

It is a cyclic number.

It is not a de Polignac number, because 20608681 - 2¹⁷ = 20477609 is a prime.

It is a super-2 number, since 2×20608681² = 849435465119522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20608661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10304340 + 10304341.

It is an arithmetic number, because the mean of its divisors is an integer number (10304341).

Almost surely, 2^20608681 is an apocalyptic number.

It is an amenable number.

20608681 is a deficient number, since it is larger than the sum of its proper divisors (1).

20608681 is an equidigital number, since it uses as much as digits as its factorization.

20608681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 20608681 is about 4539.6785128465. The cubic root of 20608681 is about 274.1679800054.

The spelling of 20608681 in words is "twenty million, six hundred eight thousand, six hundred eighty-one".