421805687 has 4 divisors (see below), whose sum is σ = 422766960. Its totient is φ = 420844416.

The previous prime is 421805677. The next prime is 421805689. The reversal of 421805687 is 786508124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 421805687 - 2²⁰ = 420757111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421805689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 479978 + ... + 480855.

It is an arithmetic number, because the mean of its divisors is an integer number (105691740).

Almost surely, 2^421805687 is an apocalyptic number.

421805687 is a deficient number, since it is larger than the sum of its proper divisors (961273).

421805687 is an equidigital number, since it uses as much as digits as its factorization.

421805687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 961272.

The product of its (nonzero) digits is 107520, while the sum is 41.

The square root of 421805687 is about 20537.9085351941. The cubic root of 421805687 is about 749.9589233800.

The spelling of 421805687 in words is "four hundred twenty-one million, eight hundred five thousand, six hundred eighty-seven".