20505456 has 60 divisors (see below), whose sum is σ = 57815992. Its totient is φ = 6784128.

The previous prime is 20505449. The next prime is 20505467. The reversal of 20505456 is 65450502.

20505456 is a `hidden beast` number, since 205 + 0 + 5 + 456 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22155 + ... + 23061.

Almost surely, 2^20505456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20505456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28907996).

20505456 is an abundant number, since it is smaller than the sum of its proper divisors (37310536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20505456 is a wasteful number, since it uses less digits than its factorization.

20505456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078 (or 1069 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The square root of 20505456 is about 4528.2950433911. The cubic root of 20505456 is about 273.7094616897.

Adding to 20505456 its reverse (65450502), we get a palindrome (85955958).

The spelling of 20505456 in words is "twenty million, five hundred five thousand, four hundred fifty-six".