20851319 has 4 divisors (see below), whose sum is σ = 21570360. Its totient is φ = 20132280.

The previous prime is 20851301. The next prime is 20851321. The reversal of 20851319 is 91315802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20851319 - 2²⁰ = 19802743 is a prime.

It is a super-2 number, since 2×20851319² = 869555008079522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 719011 = 20851319 / (2 + 0 + 8 + 5 + 1 + 3 + 1 + 9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20851291 and 20851300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20851399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359477 + ... + 359534.

It is an arithmetic number, because the mean of its divisors is an integer number (5392590).

Almost surely, 2^20851319 is an apocalyptic number.

20851319 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

20851319 is a deficient number, since it is larger than the sum of its proper divisors (719041).

20851319 is an equidigital number, since it uses as much as digits as its factorization.

20851319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719040.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 20851319 is about 4566.3244518978. The cubic root of 20851319 is about 275.2397644494.

The spelling of 20851319 in words is "twenty million, eight hundred fifty-one thousand, three hundred nineteen".