20851311 has 8 divisors (see below), whose sum is σ = 29940400. Its totient is φ = 12831552.

The previous prime is 20851301. The next prime is 20851321. The reversal of 20851311 is 11315802.

It is an interprime number because it is at equal distance from previous prime (20851301) and next prime (20851321).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20851311 - 2⁹ = 20850799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20851301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 267286 + ... + 267363.

It is an arithmetic number, because the mean of its divisors is an integer number (3742550).

Almost surely, 2^20851311 is an apocalyptic number.

20851311 is a deficient number, since it is larger than the sum of its proper divisors (9089089).

20851311 is a wasteful number, since it uses less digits than its factorization.

20851311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534665.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 20851311 is about 4566.3235759197. The cubic root of 20851311 is about 275.2397292491.

The spelling of 20851311 in words is "twenty million, eight hundred fifty-one thousand, three hundred eleven".