1321720003 has 4 divisors (see below), whose sum is σ = 1331228920. Its totient is φ = 1312211088.

The previous prime is 1321719983. The next prime is 1321720013. The reversal of 1321720003 is 3000271231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3000271231 = 17 ⋅176486543.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321720003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321720013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4754250 + ... + 4754527.

It is an arithmetic number, because the mean of its divisors is an integer number (332807230).

Almost surely, 2^1321720003 is an apocalyptic number.

1321720003 is a deficient number, since it is larger than the sum of its proper divisors (9508917).

1321720003 is an equidigital number, since it uses as much as digits as its factorization.

1321720003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9508916.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 1321720003 is about 36355.4673054824. The cubic root of 1321720003 is about 1097.4375624631.

Adding to 1321720003 its reverse (3000271231), we get a palindrome (4321991234).

The spelling of 1321720003 in words is "one billion, three hundred twenty-one million, seven hundred twenty thousand, three".