421352821 has 4 divisors (see below), whose sum is σ = 421998732. Its totient is φ = 420706912.

The previous prime is 421352783. The next prime is 421352831. The reversal of 421352821 is 128253124.

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 212868100 + 208484721 = 14590^2 + 14439^2 .

It is a cyclic number.

It is not a de Polignac number, because 421352821 - 2²³ = 412964213 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 421352821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421352831) 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, 321976 + ... + 323281.

It is an arithmetic number, because the mean of its divisors is an integer number (105499683).

Almost surely, 2^421352821 is an apocalyptic number.

It is an amenable number.

421352821 is a deficient number, since it is larger than the sum of its proper divisors (645911).

421352821 is an equidigital number, since it uses as much as digits as its factorization.

421352821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645910.

The product of its digits is 3840, while the sum is 28.

The square root of 421352821 is about 20526.8804497907. The cubic root of 421352821 is about 749.6904328344.

The spelling of 421352821 in words is "four hundred twenty-one million, three hundred fifty-two thousand, eight hundred twenty-one".