401781 has 8 divisors (see below), whose sum is σ = 539200. Its totient is φ = 266112.

The previous prime is 401773. The next prime is 401809. The reversal of 401781 is 187104.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 401781 - 2³ = 401773 is a prime.

It is a super-2 number, since 2×401781² = 322855943922, which contains 22 as substring.

It is a Duffinian number.

401781 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 401781.

It is not an unprimeable number, because it can be changed into a prime (401711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261 + ... + 933.

It is an arithmetic number, because the mean of its divisors is an integer number (67400).

2⁴⁰¹⁷⁸¹ is an apocalyptic number.

It is an amenable number.

401781 is a deficient number, since it is larger than the sum of its proper divisors (137419).

401781 is a wasteful number, since it uses less digits than its factorization.

401781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 401781 is about 633.8619723568. The cubic root of 401781 is about 73.7898224080.

Adding to 401781 its reverse (187104), we get a palindrome (588885).

The spelling of 401781 in words is "four hundred one thousand, seven hundred eighty-one".