421020421 has 4 divisors (see below), whose sum is σ = 421283052. Its totient is φ = 420757792.

The previous prime is 421020409. The next prime is 421020427. The reversal of 421020421 is 124020124.

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 352312900 + 68707521 = 18770^2 + 8289^2 .

It is a cyclic number.

It is not a de Polignac number, because 421020421 - 2⁵ = 421020389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 421020395 and 421020404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421020427) 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, 128896 + ... + 132121.

It is an arithmetic number, because the mean of its divisors is an integer number (105320763).

Almost surely, 2^421020421 is an apocalyptic number.

It is an amenable number.

421020421 is a deficient number, since it is larger than the sum of its proper divisors (262631).

421020421 is a wasteful number, since it uses less digits than its factorization.

421020421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262630.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 421020421 is about 20518.7821519699. The cubic root of 421020421 is about 749.4932404850.

Adding to 421020421 its reverse (124020124), we get a palindrome (545040545).

The spelling of 421020421 in words is "four hundred twenty-one million, twenty thousand, four hundred twenty-one".