1721516720 has 160 divisors (see below), whose sum is σ = 5041391616. Its totient is φ = 531072000.

The previous prime is 1721516701. The next prime is 1721516749. The reversal of 1721516720 is 276151271.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 620777 + ... + 623543.

Almost surely, 2^1721516720 is an apocalyptic number.

1721516720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1721516720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2520695808).

1721516720 is an abundant number, since it is smaller than the sum of its proper divisors (3319874896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1721516720 is a wasteful number, since it uses less digits than its factorization.

1721516720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2899 (or 2893 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 32.

The square root of 1721516720 is about 41491.1643606202. The cubic root of 1721516720 is about 1198.4973599201.

Adding to 1721516720 its reverse (276151271), we get a palindrome (1997667991).

It can be divided in two parts, 172151 and 6720, that added together give a palindrome (178871).

The spelling of 1721516720 in words is "one billion, seven hundred twenty-one million, five hundred sixteen thousand, seven hundred twenty".