421688 has 8 divisors (see below), whose sum is σ = 790680. Its totient is φ = 210840.

The previous prime is 421661. The next prime is 421691. The reversal of 421688 is 886124.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 421688.

It is a congruent number.

It is an unprimeable number.

421688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26348 + ... + 26363.

It is an arithmetic number, because the mean of its divisors is an integer number (98835).

2⁴²¹⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

421688 is a deficient number, since it is larger than the sum of its proper divisors (368992).

421688 is a wasteful number, since it uses less digits than its factorization.

421688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52717 (or 52713 counting only the distinct ones).

The product of its digits is 3072, while the sum is 29.

The square root of 421688 is about 649.3750842156. The cubic root of 421688 is about 74.9889168808.

The spelling of 421688 in words is "four hundred twenty-one thousand, six hundred eighty-eight".