421343423021 has 2 divisors, whose sum is σ = 421343423022. Its totient is φ = 421343423020.

The previous prime is 421343423009. The next prime is 421343423047. The reversal of 421343423021 is 120324343124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 351158167396 + 70185255625 = 592586^2 + 264925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421343423021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421343423621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210671711510 + 210671711511.

It is an arithmetic number, because the mean of its divisors is an integer number (210671711511).

Almost surely, 2^421343423021 is an apocalyptic number.

It is an amenable number.

421343423021 is a deficient number, since it is larger than the sum of its proper divisors (1).

421343423021 is an equidigital number, since it uses as much as digits as its factorization.

421343423021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 29.

Adding to 421343423021 its reverse (120324343124), we get a palindrome (541667766145).

The spelling of 421343423021 in words is "four hundred twenty-one billion, three hundred forty-three million, four hundred twenty-three thousand, twenty-one".