20851069 has 4 divisors (see below), whose sum is σ = 20860480. Its totient is φ = 20841660.

The previous prime is 20851007. The next prime is 20851097. The reversal of 20851069 is 96015802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20851069 is a prime.

It is a super-2 number, since 2×20851069² = 869534156885522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20851069.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20851769) 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, 652 + ... + 6490.

It is an arithmetic number, because the mean of its divisors is an integer number (5215120).

Almost surely, 2^20851069 is an apocalyptic number.

It is an amenable number.

20851069 is a deficient number, since it is larger than the sum of its proper divisors (9411).

20851069 is an equidigital number, since it uses as much as digits as its factorization.

20851069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9410.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 20851069 is about 4566.2970775016. The cubic root of 20851069 is about 275.2386644356.

The spelling of 20851069 in words is "twenty million, eight hundred fifty-one thousand, sixty-nine".