400491 has 32 divisors (see below), whose sum is σ = 734720. Its totient is φ = 209952.

The previous prime is 400481. The next prime is 400523. The reversal of 400491 is 194004.

400491 = 58³ + 59³.

It is not a de Polignac number, because 400491 - 2⁹ = 399979 is a prime.

400491 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (400441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2376 + ... + 2538.

It is an arithmetic number, because the mean of its divisors is an integer number (22960).

2⁴⁰⁰⁴⁹¹ is an apocalyptic number.

400491 is a deficient number, since it is larger than the sum of its proper divisors (334229).

400491 is a wasteful number, since it uses less digits than its factorization.

400491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 400491 is about 632.8435825700. The cubic root of 400491 is about 73.7107653036.

Adding to 400491 its reverse (194004), we get a palindrome (594495).

It can be divided in two parts, 4004 and 91, that added together give a triangular number (4095 = T₉₀).

The spelling of 400491 in words is "four hundred thousand, four hundred ninety-one".