1721897317 has 4 divisors (see below), whose sum is σ = 1967882656. Its totient is φ = 1475911980.

The previous prime is 1721897273. The next prime is 1721897321. The reversal of 1721897317 is 7137981271.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7137981271 = 12487 ⋅571633.

It is a cyclic number.

It is not a de Polignac number, because 1721897317 - 2¹⁵ = 1721864549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721897017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122992659 + ... + 122992672.

It is an arithmetic number, because the mean of its divisors is an integer number (491970664).

Almost surely, 2^1721897317 is an apocalyptic number.

It is an amenable number.

1721897317 is a deficient number, since it is larger than the sum of its proper divisors (245985339).

1721897317 is an equidigital number, since it uses as much as digits as its factorization.

1721897317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245985338.

The product of its digits is 148176, while the sum is 46.

The square root of 1721897317 is about 41495.7505896688. The cubic root of 1721897317 is about 1198.5856756252.

The spelling of 1721897317 in words is "one billion, seven hundred twenty-one million, eight hundred ninety-seven thousand, three hundred seventeen".