20661373 has 2 divisors, whose sum is σ = 20661374. Its totient is φ = 20661372.

The previous prime is 20661367. The next prime is 20661397. The reversal of 20661373 is 37316602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20088324 + 573049 = 4482^2 + 757^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20661373 is a prime.

It is equal to p_1309843 and since 20661373 and 1309843 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20661323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10330686 + 10330687.

It is an arithmetic number, because the mean of its divisors is an integer number (10330687).

Almost surely, 2^20661373 is an apocalyptic number.

It is an amenable number.

20661373 is a deficient number, since it is larger than the sum of its proper divisors (1).

20661373 is an equidigital number, since it uses as much as digits as its factorization.

20661373 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 20661373 is about 4545.4783026652. The cubic root of 20661373 is about 274.4014441540.

Adding to 20661373 its reverse (37316602), we get a palindrome (57977975).

The spelling of 20661373 in words is "twenty million, six hundred sixty-one thousand, three hundred seventy-three".