20665849 has 2 divisors, whose sum is σ = 20665850. Its totient is φ = 20665848.

The previous prime is 20665837. The next prime is 20665859. The reversal of 20665849 is 94856602.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16933225 + 3732624 = 4115^2 + 1932^2 .

It is a cyclic number.

It is not a de Polignac number, because 20665849 - 2¹¹ = 20663801 is a prime.

It is not a weakly prime, because it can be changed into another prime (20665819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332924 + 10332925.

It is an arithmetic number, because the mean of its divisors is an integer number (10332925).

Almost surely, 2^20665849 is an apocalyptic number.

It is an amenable number.

20665849 is a deficient number, since it is larger than the sum of its proper divisors (1).

20665849 is an equidigital number, since it uses as much as digits as its factorization.

20665849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 20665849 is about 4545.9706334291. The cubic root of 20665849 is about 274.4212578127.

The spelling of 20665849 in words is "twenty million, six hundred sixty-five thousand, eight hundred forty-nine".