20358721 has 2 divisors, whose sum is σ = 20358722. Its totient is φ = 20358720.

The previous prime is 20358719. The next prime is 20358733. The reversal of 20358721 is 12785302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19678096 + 680625 = 4436^2 + 825^2 .

It is a cyclic number.

It is not a de Polignac number, because 20358721 - 2¹ = 20358719 is a prime.

Together with 20358719, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20358721.

It is not a weakly prime, because it can be changed into another prime (20358761) 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, 10179360 + 10179361.

It is an arithmetic number, because the mean of its divisors is an integer number (10179361).

Almost surely, 2^20358721 is an apocalyptic number.

It is an amenable number.

20358721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20358721 is an equidigital number, since it uses as much as digits as its factorization.

20358721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 20358721 is about 4512.0639401498. The cubic root of 20358721 is about 273.0550189441.

The spelling of 20358721 in words is "twenty million, three hundred fifty-eight thousand, seven hundred twenty-one".