20720255 has 4 divisors (see below), whose sum is σ = 24864312. Its totient is φ = 16576200.

The previous prime is 20720237. The next prime is 20720261. The reversal of 20720255 is 55202702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55202702 = 2 ⋅27601351.

It is not a de Polignac number, because 20720255 - 2¹⁸ = 20458111 is a prime.

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 20720255.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2072021 + ... + 2072030.

It is an arithmetic number, because the mean of its divisors is an integer number (6216078).

Almost surely, 2^20720255 is an apocalyptic number.

20720255 is a deficient number, since it is larger than the sum of its proper divisors (4144057).

20720255 is an equidigital number, since it uses as much as digits as its factorization.

20720255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4144056.

The product of its (nonzero) digits is 1400, while the sum is 23.

The square root of 20720255 is about 4551.9506807522. The cubic root of 20720255 is about 274.6618653985.

Adding to 20720255 its reverse (55202702), we get a palindrome (75922957).

The spelling of 20720255 in words is "twenty million, seven hundred twenty thousand, two hundred fifty-five".