721130 has 16 divisors (see below), whose sum is σ = 1333800. Its totient is φ = 280512.

The previous prime is 721129. The next prime is 721139. The reversal of 721130 is 31127.

It can be written as a sum of positive squares in 4 ways, for example, as 717409 + 3721 = 847^2 + 61^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (721139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 605 + ... + 1344.

2⁷²¹¹³⁰ is an apocalyptic number.

721130 is a deficient number, since it is larger than the sum of its proper divisors (612670).

721130 is a wasteful number, since it uses less digits than its factorization.

721130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1993.

The product of its (nonzero) digits is 42, while the sum is 14.

The square root of 721130 is about 849.1937352572. The cubic root of 721130 is about 89.6749591946.

Adding to 721130 its reverse (31127), we get a palindrome (752257).

The spelling of 721130 in words is "seven hundred twenty-one thousand, one hundred thirty".