1321200021 has 8 divisors (see below), whose sum is σ = 1786411584. Its totient is φ = 868394240.

The previous prime is 1321199977. The next prime is 1321200047. The reversal of 1321200021 is 1200021231.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1321200021 - 2¹¹ = 1321197973 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321200121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3101196 + ... + 3101621.

It is an arithmetic number, because the mean of its divisors is an integer number (223301448).

Almost surely, 2^1321200021 is an apocalyptic number.

It is an amenable number.

1321200021 is a deficient number, since it is larger than the sum of its proper divisors (465211563).

1321200021 is an equidigital number, since it uses as much as digits as its factorization.

1321200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6202891.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1321200021 is about 36348.3152429380. The cubic root of 1321200021 is about 1097.2936281383.

Adding to 1321200021 its reverse (1200021231), we get a palindrome (2521221252).

The spelling of 1321200021 in words is "one billion, three hundred twenty-one million, two hundred thousand, twenty-one".