1721472721 has 4 divisors (see below), whose sum is σ = 1727080432. Its totient is φ = 1715865012.

The previous prime is 1721472691. The next prime is 1721472737. The reversal of 1721472721 is 1272741271.

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.

It is a cyclic number.

It is not a de Polignac number, because 1721472721 - 2¹⁷ = 1721341649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1721472761) 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, 2803395 + ... + 2804008.

It is an arithmetic number, because the mean of its divisors is an integer number (431770108).

Almost surely, 2^1721472721 is an apocalyptic number.

It is an amenable number.

1721472721 is a deficient number, since it is larger than the sum of its proper divisors (5607711).

1721472721 is an equidigital number, since it uses as much as digits as its factorization.

1721472721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5607710.

The product of its digits is 10976, while the sum is 34.

The square root of 1721472721 is about 41490.6341359107. The cubic root of 1721472721 is about 1198.4871493242.

The spelling of 1721472721 in words is "one billion, seven hundred twenty-one million, four hundred seventy-two thousand, seven hundred twenty-one".