405720 has 144 divisors (see below), whose sum is σ = 1600560. Its totient is φ = 88704.

The previous prime is 405719. The next prime is 405731. The reversal of 405720 is 27504.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 405693 and 405702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 17629 + ... + 17651.

It is an arithmetic number, because the mean of its divisors is an integer number (11115).

2⁴⁰⁵⁷²⁰ is an apocalyptic number.

405720 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 405720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (800280).

405720 is an abundant number, since it is smaller than the sum of its proper divisors (1194840).

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

405720 is a wasteful number, since it uses less digits than its factorization.

405720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54 (or 40 counting only the distinct ones).

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

The square root of 405720 is about 636.9615373003. The cubic root of 405720 is about 74.0301800443.

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

The spelling of 405720 in words is "four hundred five thousand, seven hundred twenty".