20321320 has 16 divisors (see below), whose sum is σ = 45723060. Its totient is φ = 8128512.

The previous prime is 20321303. The next prime is 20321339. The reversal of 20321320 is 2312302.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18818244 + 1503076 = 4338^2 + 1226^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20321320.

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, 253977 + ... + 254056.

Almost surely, 2^20321320 is an apocalyptic number.

20321320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20321320 is an abundant number, since it is smaller than the sum of its proper divisors (25401740).

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

20321320 is a wasteful number, since it uses less digits than its factorization.

20321320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508044 (or 508040 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 20321320 is about 4507.9174792802. The cubic root of 20321320 is about 272.8877066824.

Adding to 20321320 its reverse (2312302), we get a palindrome (22633622).

The spelling of 20321320 in words is "twenty million, three hundred twenty-one thousand, three hundred twenty".