20778259 has 4 divisors (see below), whose sum is σ = 20801016. Its totient is φ = 20755504.

The previous prime is 20778253. The next prime is 20778283. The reversal of 20778259 is 95287702.

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 20778259 - 2¹⁹ = 20253971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20778253) 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, 9949 + ... + 11854.

It is an arithmetic number, because the mean of its divisors is an integer number (5200254).

Almost surely, 2^20778259 is an apocalyptic number.

20778259 is a deficient number, since it is larger than the sum of its proper divisors (22757).

20778259 is an equidigital number, since it uses as much as digits as its factorization.

20778259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22756.

The product of its (nonzero) digits is 70560, while the sum is 40.

The square root of 20778259 is about 4558.3175624346. The cubic root of 20778259 is about 274.9179215102.

The spelling of 20778259 in words is "twenty million, seven hundred seventy-eight thousand, two hundred fifty-nine".