20509824 has 32 divisors (see below), whose sum is σ = 54480240. Its totient is φ = 6836480.

The previous prime is 20509793. The next prime is 20509831. The reversal of 20509824 is 42890502.

It is a tau number, because it is divible by the number of its divisors (32).

It is a junction number, because it is equal to n+sod(n) for n = 20509791 and 20509800.

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, 26322 + ... + 27089.

Almost surely, 2^20509824 is an apocalyptic number.

20509824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20509824 is an abundant number, since it is smaller than the sum of its proper divisors (33970416).

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

20509824 is an equidigital number, since it uses as much as digits as its factorization.

20509824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53428 (or 53416 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 20509824 is about 4528.7773184382. Note that the first 3 decimals coincide. The cubic root of 20509824 is about 273.7288951850.

The spelling of 20509824 in words is "twenty million, five hundred nine thousand, eight hundred twenty-four".