721620340 has 48 divisors (see below), whose sum is σ = 1791619200. Its totient is φ = 238879872.

The previous prime is 721620313. The next prime is 721620349. The reversal of 721620340 is 43026127.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721620349) 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 15 ways as a sum of consecutive naturals, for example, 84810 + ... + 92929.

It is an arithmetic number, because the mean of its divisors is an integer number (37325400).

Almost surely, 2^721620340 is an apocalyptic number.

721620340 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

721620340 is an abundant number, since it is smaller than the sum of its proper divisors (1069998860).

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

721620340 is a wasteful number, since it uses less digits than its factorization.

721620340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177784 (or 177782 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 721620340 is about 26862.9920150381. The cubic root of 721620340 is about 896.9527973646.

Adding to 721620340 its reverse (43026127), we get a palindrome (764646467).

It can be divided in two parts, 7216 and 20340, that added together give a square (27556 = 166²).

The spelling of 721620340 in words is "seven hundred twenty-one million, six hundred twenty thousand, three hundred forty".