705621 has 8 divisors (see below), whose sum is σ = 1075264. Its totient is φ = 403200.

The previous prime is 705613. The next prime is 705631. The reversal of 705621 is 126507.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 705621 - 2³ = 705613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 33601 = 705621 / (7 + 0 + 5 + 6 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

705621 is a lucky number.

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 705621.

It is not an unprimeable number, because it can be changed into a prime (705631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16780 + ... + 16821.

It is an arithmetic number, because the mean of its divisors is an integer number (134408).

2⁷⁰⁵⁶²¹ is an apocalyptic number.

It is an amenable number.

705621 is a deficient number, since it is larger than the sum of its proper divisors (369643).

705621 is a wasteful number, since it uses less digits than its factorization.

705621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33611.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 705621 is about 840.0124999070. The cubic root of 705621 is about 89.0274291588.

Subtracting from 705621 its sum of digits (21), we obtain a square (705600 = 840²).

It can be divided in two parts, 705 and 621, that added together give a triangular number (1326 = T₅₁).

The spelling of 705621 in words is "seven hundred five thousand, six hundred twenty-one".