20851313 has 32 divisors (see below), whose sum is σ = 26265600. Its totient is φ = 16511040.

The previous prime is 20851301. The next prime is 20851321. The reversal of 20851313 is 31315802.

It is not a de Polignac number, because 20851313 - 2²² = 16657009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20851213) 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 in 31 ways as a sum of consecutive naturals, for example, 393395 + ... + 393447.

It is an arithmetic number, because the mean of its divisors is an integer number (820800).

Almost surely, 2^20851313 is an apocalyptic number.

It is an amenable number.

20851313 is a deficient number, since it is larger than the sum of its proper divisors (5414287).

20851313 is an equidigital number, since it uses as much as digits as its factorization.

20851313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 20851313 is about 4566.3237949142. The cubic root of 20851313 is about 275.2397380491.

The spelling of 20851313 in words is "twenty million, eight hundred fifty-one thousand, three hundred thirteen".