20778269 has 4 divisors (see below), whose sum is σ = 21681696. Its totient is φ = 19874844.

The previous prime is 20778253. The next prime is 20778283. The reversal of 20778269 is 96287702.

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.

It is a cyclic number.

It is not a de Polignac number, because 20778269 - 2⁴ = 20778253 is a prime.

It is a super-2 number, since 2×20778269² = 863472925272722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20778299) 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 3 ways as a sum of consecutive naturals, for example, 451679 + ... + 451724.

It is an arithmetic number, because the mean of its divisors is an integer number (5420424).

Almost surely, 2^20778269 is an apocalyptic number.

It is an amenable number.

20778269 is a deficient number, since it is larger than the sum of its proper divisors (903427).

20778269 is an equidigital number, since it uses as much as digits as its factorization.

20778269 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903426.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 20778269 is about 4558.3186593304. The cubic root of 20778269 is about 274.9179656137.

The spelling of 20778269 in words is "twenty million, seven hundred seventy-eight thousand, two hundred sixty-nine".