20685629 has 2 divisors, whose sum is σ = 20685630. Its totient is φ = 20685628.

The previous prime is 20685601. The next prime is 20685631. The reversal of 20685629 is 92658602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19123129 + 1562500 = 4373^2 + 1250^2 .

It is a cyclic number.

It is not a de Polignac number, because 20685629 - 2⁸ = 20685373 is a prime.

Together with 20685631, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20685592 and 20685601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20685659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10342814 + 10342815.

It is an arithmetic number, because the mean of its divisors is an integer number (10342815).

Almost surely, 2^20685629 is an apocalyptic number.

It is an amenable number.

20685629 is a deficient number, since it is larger than the sum of its proper divisors (1).

20685629 is an equidigital number, since it uses as much as digits as its factorization.

20685629 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 20685629 is about 4548.1456660929. The cubic root of 20685629 is about 274.5087825919.

The spelling of 20685629 in words is "twenty million, six hundred eighty-five thousand, six hundred twenty-nine".