721020 has 48 divisors (see below), whose sum is σ = 2062368. Its totient is φ = 188160.

The previous prime is 721013. The next prime is 721037. The reversal of 721020 is 20127.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 720987 and 721005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3562 + ... + 3758.

It is an arithmetic number, because the mean of its divisors is an integer number (42966).

2⁷²¹⁰²⁰ 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 721020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031184).

721020 is an abundant number, since it is smaller than the sum of its proper divisors (1341348).

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

721020 is a wasteful number, since it uses less digits than its factorization.

721020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 28, while the sum is 12.

The square root of 721020 is about 849.1289654699. The cubic root of 721020 is about 89.6703993385.

Adding to 721020 its reverse (20127), we get a palindrome (741147).

The spelling of 721020 in words is "seven hundred twenty-one thousand, twenty", and thus it is an iban number.