20531320 has 16 divisors (see below), whose sum is σ = 46195560. Its totient is φ = 8212512.

The previous prime is 20531297. The next prime is 20531347. The reversal of 20531320 is 2313502.

It is a junction number, because it is equal to n+sod(n) for n = 20531294 and 20531303.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256602 + ... + 256681.

Almost surely, 2^20531320 is an apocalyptic number.

20531320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20531320 is an abundant number, since it is smaller than the sum of its proper divisors (25664240).

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

20531320 is a wasteful number, since it uses less digits than its factorization.

20531320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513294 (or 513290 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 20531320 is about 4531.1499644130. The cubic root of 20531320 is about 273.8244920050.

Adding to 20531320 its reverse (2313502), we get a palindrome (22844822).

The spelling of 20531320 in words is "twenty million, five hundred thirty-one thousand, three hundred twenty".