20650661 has 2 divisors, whose sum is σ = 20650662. Its totient is φ = 20650660.

The previous prime is 20650657. The next prime is 20650667. The reversal of 20650661 is 16605602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19088161 + 1562500 = 4369^2 + 1250^2 .

It is a cyclic number.

It is not a de Polignac number, because 20650661 - 2² = 20650657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20650661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20650667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10325330 + 10325331.

It is an arithmetic number, because the mean of its divisors is an integer number (10325331).

Almost surely, 2^20650661 is an apocalyptic number.

It is an amenable number.

20650661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20650661 is an equidigital number, since it uses as much as digits as its factorization.

20650661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20650661 is about 4544.2998360584. The cubic root of 20650661 is about 274.3540143212.

The spelling of 20650661 in words is "twenty million, six hundred fifty thousand, six hundred sixty-one".