1720204121 has 8 divisors (see below), whose sum is σ = 1852852320. Its totient is φ = 1591767072.

The previous prime is 1720204069. The next prime is 1720204151. The reversal of 1720204121 is 1214020271.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1720204121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1720204093 and 1720204102.

It is not an unprimeable number, because it can be changed into a prime (1720204151) 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, 1051940 + ... + 1053573.

It is an arithmetic number, because the mean of its divisors is an integer number (231606540).

Almost surely, 2^1720204121 is an apocalyptic number.

It is an amenable number.

1720204121 is a deficient number, since it is larger than the sum of its proper divisors (132648199).

1720204121 is a wasteful number, since it uses less digits than its factorization.

1720204121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2105575.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 1720204121 is about 41475.3435308256. The cubic root of 1720204121 is about 1198.1926777347.

Adding to 1720204121 its reverse (1214020271), we get a palindrome (2934224392).

The spelling of 1720204121 in words is "one billion, seven hundred twenty million, two hundred four thousand, one hundred twenty-one".