20829251 has 2 divisors, whose sum is σ = 20829252. Its totient is φ = 20829250.

The previous prime is 20829239. The next prime is 20829253. The reversal of 20829251 is 15292802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20829251 is a prime.

It is a Sophie Germain prime.

Together with 20829253, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20829253) 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, 10414625 + 10414626.

It is an arithmetic number, because the mean of its divisors is an integer number (10414626).

Almost surely, 2^20829251 is an apocalyptic number.

20829251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20829251 is an equidigital number, since it uses as much as digits as its factorization.

20829251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 20829251 is about 4563.9074267562. The cubic root of 20829251 is about 275.1426301436.

The spelling of 20829251 in words is "twenty million, eight hundred twenty-nine thousand, two hundred fifty-one".