1321200020 has 24 divisors (see below), whose sum is σ = 3170880384. Its totient is φ = 452982816.

The previous prime is 1321199977. The next prime is 1321200047. The reversal of 1321200020 is 200021231.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1321199974 and 1321200010.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4718432 + ... + 4718711.

It is an arithmetic number, because the mean of its divisors is an integer number (132120016).

Almost surely, 2^1321200020 is an apocalyptic number.

1321200020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321200020 is an abundant number, since it is smaller than the sum of its proper divisors (1849680364).

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

1321200020 is a wasteful number, since it uses less digits than its factorization.

1321200020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9437159 (or 9437157 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 1321200020 is about 36348.3152291822. The cubic root of 1321200020 is about 1097.2936278615.

Adding to 1321200020 its reverse (200021231), we get a palindrome (1521221251).

The spelling of 1321200020 in words is "one billion, three hundred twenty-one million, two hundred thousand, twenty".