401688 has 48 divisors (see below), whose sum is σ = 1244880. Its totient is φ = 114624.

The previous prime is 401671. The next prime is 401689. The reversal of 401688 is 886104.

It is a super-2 number, since 2×401688² = 322706498688, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401689) by changing a digit.

401688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106 + ... + 902.

It is an arithmetic number, because the mean of its divisors is an integer number (25935).

2⁴⁰¹⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 401688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (622440).

401688 is an abundant number, since it is smaller than the sum of its proper divisors (843192).

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

401688 is a wasteful number, since it uses less digits than its factorization.

401688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 809 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 401688 is about 633.7886082914. The cubic root of 401688 is about 73.7841286071.

Subtracting 401688 from its reverse (886104), we obtain a square (484416 = 696²).

It can be divided in two parts, 401 and 688, that added together give a square (1089 = 33²).

The spelling of 401688 in words is "four hundred one thousand, six hundred eighty-eight".