20505324 has 72 divisors (see below), whose sum is σ = 57021888. Its totient is φ = 5715360.

The previous prime is 20505307. The next prime is 20505341. The reversal of 20505324 is 42350502.

It is an interprime number because it is at equal distance from previous prime (20505307) and next prime (20505341).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 20505324.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24879 + ... + 25689.

Almost surely, 2^20505324 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 20505324, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28510944).

20505324 is an abundant number, since it is smaller than the sum of its proper divisors (36516564).

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

20505324 is a wasteful number, since it uses less digits than its factorization.

20505324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875 (or 866 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 21.

The square root of 20505324 is about 4528.2804683456. The cubic root of 20505324 is about 273.7088743708.

Adding to 20505324 its reverse (42350502), we get a palindrome (62855826).

The spelling of 20505324 in words is "twenty million, five hundred five thousand, three hundred twenty-four".