406621 has 4 divisors (see below), whose sum is σ = 409500. Its totient is φ = 403744.

The previous prime is 406591. The next prime is 406631. The reversal of 406621 is 126604.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 235225 + 171396 = 485^2 + 414^2 .

It is a cyclic number.

It is not a de Polignac number, because 406621 - 2¹⁷ = 275549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (406631) 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, 1216 + ... + 1513.

It is an arithmetic number, because the mean of its divisors is an integer number (102375).

2⁴⁰⁶⁶²¹ is an apocalyptic number.

It is an amenable number.

406621 is a deficient number, since it is larger than the sum of its proper divisors (2879).

406621 is a wasteful number, since it uses less digits than its factorization.

406621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2878.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 406621 is about 637.6684091281. The cubic root of 406621 is about 74.0849402053.

The spelling of 406621 in words is "four hundred six thousand, six hundred twenty-one".