421004243021 has 4 divisors (see below), whose sum is σ = 421151604732. Its totient is φ = 420856881312.

The previous prime is 421004242949. The next prime is 421004243047. The reversal of 421004243021 is 120342400124.

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 317053455625 + 103950787396 = 563075^2 + 322414^2 .

It is a cyclic number.

It is not a de Polignac number, because 421004243021 - 2³⁸ = 146126336077 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421004243081) 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, 73676570 + ... + 73682283.

It is an arithmetic number, because the mean of its divisors is an integer number (105287901183).

Almost surely, 2^421004243021 is an apocalyptic number.

It is an amenable number.

421004243021 is a deficient number, since it is larger than the sum of its proper divisors (147361711).

421004243021 is a wasteful number, since it uses less digits than its factorization.

421004243021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147361710.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 421004243021 its reverse (120342400124), we get a palindrome (541346643145).

The spelling of 421004243021 in words is "four hundred twenty-one billion, four million, two hundred forty-three thousand, twenty-one".