406491 has 4 divisors (see below), whose sum is σ = 541992. Its totient is φ = 270992.

The previous prime is 406481. The next prime is 406499. The reversal of 406491 is 194604.

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

It is a cyclic number.

It is not a de Polignac number, because 406491 - 2¹⁴ = 390107 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (406499) 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, 67746 + ... + 67751.

It is an arithmetic number, because the mean of its divisors is an integer number (135498).

2⁴⁰⁶⁴⁹¹ is an apocalyptic number.

406491 is a deficient number, since it is larger than the sum of its proper divisors (135501).

406491 is a wasteful number, since it uses less digits than its factorization.

406491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135500.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 406491 is about 637.5664671232. The cubic root of 406491 is about 74.0770441803.

The spelling of 406491 in words is "four hundred six thousand, four hundred ninety-one".