421551421 has 4 divisors (see below), whose sum is σ = 427326172. Its totient is φ = 415776672.

The previous prime is 421551373. The next prime is 421551433. The reversal of 421551421 is 124155124.

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

It can be written as a sum of positive squares in 2 ways, for example, as 114811225 + 306740196 = 10715^2 + 17514^2 .

It is a cyclic number.

It is not a de Polignac number, because 421551421 - 2¹⁵ = 421518653 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 (421551491) 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, 2887266 + ... + 2887411.

It is an arithmetic number, because the mean of its divisors is an integer number (106831543).

Almost surely, 2^421551421 is an apocalyptic number.

It is an amenable number.

421551421 is a deficient number, since it is larger than the sum of its proper divisors (5774751).

421551421 is an equidigital number, since it uses as much as digits as its factorization.

421551421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5774750.

The product of its digits is 1600, while the sum is 25.

The square root of 421551421 is about 20531.7174391233. The cubic root of 421551421 is about 749.8082004362.

The spelling of 421551421 in words is "four hundred twenty-one million, five hundred fifty-one thousand, four hundred twenty-one".