721315740 has 96 divisors (see below), whose sum is σ = 2095458624. Its totient is φ = 185241600.

The previous prime is 721315723. The next prime is 721315757. The reversal of 721315740 is 47513127.

It is an interprime number because it is at equal distance from previous prime (721315723) and next prime (721315757).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 721315698 and 721315707.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 222612 + ... + 225828.

It is an arithmetic number, because the mean of its divisors is an integer number (21827694).

Almost surely, 2^721315740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721315740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1047729312).

721315740 is an abundant number, since it is smaller than the sum of its proper divisors (1374142884).

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

721315740 is a wasteful number, since it uses less digits than its factorization.

721315740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3367 (or 3365 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 721315740 is about 26857.3219066980. The cubic root of 721315740 is about 896.8265766650.

Adding to 721315740 its reverse (47513127), we get a palindrome (768828867).

The spelling of 721315740 in words is "seven hundred twenty-one million, three hundred fifteen thousand, seven hundred forty".