20531255 has 4 divisors (see below), whose sum is σ = 24637512. Its totient is φ = 16425000.

The previous prime is 20531243. The next prime is 20531297. The reversal of 20531255 is 55213502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55213502 = 2 ⋅27606751.

It is not a de Polignac number, because 20531255 - 2¹² = 20527159 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 20531255.

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, 2053121 + ... + 2053130.

It is an arithmetic number, because the mean of its divisors is an integer number (6159378).

Almost surely, 2^20531255 is an apocalyptic number.

20531255 is a deficient number, since it is larger than the sum of its proper divisors (4106257).

20531255 is an equidigital number, since it uses as much as digits as its factorization.

20531255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4106256.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 20531255 is about 4531.1427918352. The cubic root of 20531255 is about 273.8242030381.

Adding to 20531255 its reverse (55213502), we get a palindrome (75744757).

The spelling of 20531255 in words is "twenty million, five hundred thirty-one thousand, two hundred fifty-five".