421686 has 40 divisors (see below), whose sum is σ = 1001880. Its totient is φ = 132192.

The previous prime is 421661. The next prime is 421691. The reversal of 421686 is 686124.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

421686 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 19 ways as a sum of consecutive naturals, for example, 3010 + ... + 3146.

It is an arithmetic number, because the mean of its divisors is an integer number (25047).

2⁴²¹⁶⁸⁶ is an apocalyptic number.

421686 is the 411-st heptagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 421686, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (500940).

421686 is an abundant number, since it is smaller than the sum of its proper divisors (580194).

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

421686 is a wasteful number, since it uses less digits than its factorization.

421686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 161 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 421686 is about 649.3735442717. The cubic root of 421686 is about 74.9887983271.

It can be divided in two parts, 42 and 1686, that added together give a cube (1728 = 12³).

The spelling of 421686 in words is "four hundred twenty-one thousand, six hundred eighty-six".