401840 has 20 divisors (see below), whose sum is σ = 934464. Its totient is φ = 160704.

The previous prime is 401839. The next prime is 401861. The reversal of 401840 is 48104.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×401840² = 322950771200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (17) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2432 + ... + 2591.

2⁴⁰¹⁸⁴⁰ is an apocalyptic number.

401840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

401840 is an abundant number, since it is smaller than the sum of its proper divisors (532624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

401840 is a wasteful number, since it uses less digits than its factorization.

401840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5036 (or 5030 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 401840 is about 633.9085107490. The cubic root of 401840 is about 73.7934341488.

Adding to 401840 its reverse (48104), we get a palindrome (449944).

The spelling of 401840 in words is "four hundred one thousand, eight hundred forty".