20953871 has 2 divisors, whose sum is σ = 20953872. Its totient is φ = 20953870.

The previous prime is 20953853. The next prime is 20953873. The reversal of 20953871 is 17835902.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20953871 is a prime.

It is a Sophie Germain prime.

Together with 20953873, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20953873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10476935 + 10476936.

It is an arithmetic number, because the mean of its divisors is an integer number (10476936).

Almost surely, 2^20953871 is an apocalyptic number.

20953871 is a deficient number, since it is larger than the sum of its proper divisors (1).

20953871 is an equidigital number, since it uses as much as digits as its factorization.

20953871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20953871 is about 4577.5398414432. The cubic root of 20953871 is about 275.6902593643.

The spelling of 20953871 in words is "twenty million, nine hundred fifty-three thousand, eight hundred seventy-one".