721396 has 12 divisors (see below), whose sum is σ = 1359652. Its totient is φ = 332928.

The previous prime is 721387. The next prime is 721397. The reversal of 721396 is 693127.

It can be written as a sum of positive squares in 2 ways, for example, as 211600 + 509796 = 460^2 + 714^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721397) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6885 + ... + 6988.

2⁷²¹³⁹⁶ is an apocalyptic number.

It is an amenable number.

721396 is a deficient number, since it is larger than the sum of its proper divisors (638256).

721396 is a wasteful number, since it uses less digits than its factorization.

721396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13890 (or 13888 counting only the distinct ones).

The product of its digits is 2268, while the sum is 28.

The square root of 721396 is about 849.3503399658. The cubic root of 721396 is about 89.6859838397.

The spelling of 721396 in words is "seven hundred twenty-one thousand, three hundred ninety-six".