409921 has 4 divisors (see below), whose sum is σ = 434052. Its totient is φ = 385792.

The previous prime is 409909. The next prime is 409933. The reversal of 409921 is 129904.

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

It is an interprime number because it is at equal distance from previous prime (409909) and next prime (409933).

It can be written as a sum of positive squares in 2 ways, for example, as 297025 + 112896 = 545^2 + 336^2 .

It is a cyclic number.

It is not a de Polignac number, because 409921 - 2⁵ = 409889 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 (409901) 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, 12040 + ... + 12073.

It is an arithmetic number, because the mean of its divisors is an integer number (108513).

2⁴⁰⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

409921 is a deficient number, since it is larger than the sum of its proper divisors (24131).

409921 is a wasteful number, since it uses less digits than its factorization.

409921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24130.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 409921 is about 640.2507321355. The cubic root of 409921 is about 74.2848166629.

The spelling of 409921 in words is "four hundred nine thousand, nine hundred twenty-one".