421021243 has 4 divisors (see below), whose sum is σ = 421080408. Its totient is φ = 420962080.

The previous prime is 421021193. The next prime is 421021259. The reversal of 421021243 is 342120124.

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 421021243 - 2⁹ = 421020731 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 421021243.

It is not an unprimeable number, because it can be changed into a prime (421021283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17173 + ... + 33718.

It is an arithmetic number, because the mean of its divisors is an integer number (105270102).

Almost surely, 2^421021243 is an apocalyptic number.

421021243 is a deficient number, since it is larger than the sum of its proper divisors (59165).

421021243 is an equidigital number, since it uses as much as digits as its factorization.

421021243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59164.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 421021243 is about 20518.8021823887. The cubic root of 421021243 is about 749.4937282547.

Adding to 421021243 its reverse (342120124), we get a palindrome (763141367).

The spelling of 421021243 in words is "four hundred twenty-one million, twenty-one thousand, two hundred forty-three".