721640370 has 96 divisors (see below), whose sum is σ = 1935501120. Its totient is φ = 172022400.

The previous prime is 721640363. The next prime is 721640383. The reversal of 721640370 is 73046127.

721640370 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×721640370² = 1041529647227473800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 219801 + ... + 223059.

It is an arithmetic number, because the mean of its divisors is an integer number (20161470).

Almost surely, 2^721640370 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721640370, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (967750560).

721640370 is an abundant number, since it is smaller than the sum of its proper divisors (1213860750).

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

721640370 is a wasteful number, since it uses less digits than its factorization.

721640370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3352 (or 3341 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 30.

The square root of 721640370 is about 26863.3648301921. The cubic root of 721640370 is about 896.9610961876.

Adding to 721640370 its reverse (73046127), we get a palindrome (794686497).

It can be divided in two parts, 7216 and 40370, that added together give a triangular number (47586 = T₃₀₈).

The spelling of 721640370 in words is "seven hundred twenty-one million, six hundred forty thousand, three hundred seventy".