20456 has 8 divisors (see below), whose sum is σ = 38370. Its totient is φ = 10224.

The previous prime is 20443. The next prime is 20477. The reversal of 20456 is 65402.

It can be written as a sum of positive squares in only one way, i.e., 17956 + 2500 = 134^2 + 50^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a nialpdrome in base 14.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20456.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271 + ... + 1286.

2²⁰⁴⁵⁶ is an apocalyptic number.

It is an amenable number.

20456 is a deficient number, since it is larger than the sum of its proper divisors (17914).

20456 is a wasteful number, since it uses less digits than its factorization.

20456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2563 (or 2559 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20456 is about 143.0244734302. The cubic root of 20456 is about 27.3489236197.

Adding to 20456 its reverse (65402), we get a palindrome (85858).

The spelling of 20456 in words is "twenty thousand, four hundred fifty-six".