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20953 = 23911

20953 has 4 divisors (see below), whose sum is σ = 21888. Its totient is φ = 20020.

The previous prime is 20947. The next prime is 20959. The reversal of 20953 is 35902.

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 an interprime number because it is at equal distance from previous prime (20947) and next prime (20959).

It is a cyclic number.

It is not a de Polignac number, because 20953 - 25 = 20921 is a prime.

It is a Duffinian number.

20953 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 20953.

It is not an unprimeable number, because it can be changed into a prime (20959) 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, 433 + ... + 478.

It is an arithmetic number, because the mean of its divisors is an integer number (5472).

220953 is an apocalyptic number.

20953 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20953 is a deficient number, since it is larger than the sum of its proper divisors (935).

20953 is an equidigital number, since it uses as much as digits as its factorization.

20953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 934.

The product of its (nonzero) digits is 270, while the sum is 19.

The square root of 20953 is about 144.7515112184. The cubic root of 20953 is about 27.5686439393.

It can be divided in two parts, 209 and 53, that added together give a palindrome (262).

The spelling of 20953 in words is "twenty thousand, nine hundred fifty-three".

Divisors: 1 23 911 20953