20686357 has 2 divisors, whose sum is σ = 20686358. Its totient is φ = 20686356.

The previous prime is 20686343. The next prime is 20686363. The reversal of 20686357 is 75368602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19838116 + 848241 = 4454^2 + 921^2 .

It is a cyclic number.

It is not a de Polignac number, because 20686357 - 2¹¹ = 20684309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20606357) 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, 10343178 + 10343179.

It is an arithmetic number, because the mean of its divisors is an integer number (10343179).

Almost surely, 2^20686357 is an apocalyptic number.

It is an amenable number.

20686357 is a deficient number, since it is larger than the sum of its proper divisors (1).

20686357 is an equidigital number, since it uses as much as digits as its factorization.

20686357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60480, while the sum is 37.

The square root of 20686357 is about 4548.2256980058. The cubic root of 20686357 is about 274.5120028638.

The spelling of 20686357 in words is "twenty million, six hundred eighty-six thousand, three hundred fifty-seven".