720405 has 24 divisors (see below), whose sum is σ = 1427712. Its totient is φ = 329184.

The previous prime is 720403. The next prime is 720407. The reversal of 720405 is 504027.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (720403) and next prime (720407).

It is not a de Polignac number, because 720405 - 2¹ = 720403 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 829 + ... + 1458.

It is an arithmetic number, because the mean of its divisors is an integer number (59488).

2⁷²⁰⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

720405 is a deficient number, since it is larger than the sum of its proper divisors (707307).

720405 is a wasteful number, since it uses less digits than its factorization.

720405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2305 (or 2302 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 18.

The square root of 720405 is about 848.7667524120. The cubic root of 720405 is about 89.6448970489.

It can be divided in two parts, 720 and 405, that multiplied together give a square (291600 = 540²).

The spelling of 720405 in words is "seven hundred twenty thousand, four hundred five".