721623 has 12 divisors (see below), whose sum is σ = 1119480. Its totient is φ = 412272.

The previous prime is 721621. The next prime is 721631. The reversal of 721623 is 326127.

It is a happy number.

721623 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 721623 - 2¹ = 721621 is a prime.

It is a super-3 number, since 3×721623³ = 1127333350781494101, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 721623.

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 721623.

It is not an unprimeable number, because it can be changed into a prime (721621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2308 + ... + 2601.

It is an arithmetic number, because the mean of its divisors is an integer number (93290).

2⁷²¹⁶²³ is an apocalyptic number.

721623 is a deficient number, since it is larger than the sum of its proper divisors (397857).

721623 is a wasteful number, since it uses less digits than its factorization.

721623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4926 (or 4919 counting only the distinct ones).

The product of its digits is 504, while the sum is 21.

The square root of 721623 is about 849.4839610022. The cubic root of 721623 is about 89.6953899464.

The spelling of 721623 in words is "seven hundred twenty-one thousand, six hundred twenty-three".