721212 has 12 divisors (see below), whose sum is σ = 1682856. Its totient is φ = 240400.

The previous prime is 721207. The next prime is 721213. The reversal of 721212 is 212127.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (15) coincides with the sum of the digits of its prime factors.

It is an alternating number because its digits alternate between odd and even.

721212 is a modest number, since divided by 1212 gives 72 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 721191 and 721200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721213) by changing a digit.

721212 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30039 + ... + 30062.

It is an arithmetic number, because the mean of its divisors is an integer number (140238).

2⁷²¹²¹² is an apocalyptic number.

It is an amenable number.

721212 is an abundant number, since it is smaller than the sum of its proper divisors (961644).

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

721212 is a wasteful number, since it uses less digits than its factorization.

721212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60108 (or 60106 counting only the distinct ones).

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

The square root of 721212 is about 849.2420149757. The cubic root of 721212 is about 89.6783580584.

Adding to 721212 its reverse (212127), we get a palindrome (933339).

The spelling of 721212 in words is "seven hundred twenty-one thousand, two hundred twelve", and thus it is an iban number.