721140 has 96 divisors (see below), whose sum is σ = 2467584. Its totient is φ = 153600.

The previous prime is 721139. The next prime is 721141. The reversal of 721140 is 41127.

721140 = T₁₀₄ + T₁₀₅ + ... + T₁₇₅.

It is an interprime number because it is at equal distance from previous prime (721139) and next prime (721141).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721140.

It is not an unprimeable number, because it can be changed into a prime (721141) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7090 + ... + 7190.

It is an arithmetic number, because the mean of its divisors is an integer number (25704).

2⁷²¹¹⁴⁰ is an apocalyptic number.

721140 is a gapful number since it is divisible by the number (70) 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 721140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1233792).

721140 is an abundant number, since it is smaller than the sum of its proper divisors (1746444).

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

721140 is a wasteful number, since it uses less digits than its factorization.

721140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 721140 is about 849.1996231747. The cubic root of 721140 is about 89.6753737040.

Adding to 721140 its reverse (41127), we get a palindrome (762267).

It can be divided in two parts, 721 and 140, that added together give a triangular number (861 = T₄₁).

The spelling of 721140 in words is "seven hundred twenty-one thousand, one hundred forty", and thus it is an iban number.