20290661 has 2 divisors, whose sum is σ = 20290662. Its totient is φ = 20290660.

The previous prime is 20290657. The next prime is 20290693. The reversal of 20290661 is 16609202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10562500 + 9728161 = 3250^2 + 3119^2 .

It is a cyclic number.

It is not a de Polignac number, because 20290661 - 2² = 20290657 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20290661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20290261) 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, 10145330 + 10145331.

It is an arithmetic number, because the mean of its divisors is an integer number (10145331).

Almost surely, 2^20290661 is an apocalyptic number.

It is an amenable number.

20290661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20290661 is an equidigital number, since it uses as much as digits as its factorization.

20290661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 20290661 is about 4504.5156232385. The cubic root of 20290661 is about 272.7504013752.

Adding to 20290661 its reverse (16609202), we get a palindrome (36899863).

The spelling of 20290661 in words is "twenty million, two hundred ninety thousand, six hundred sixty-one".