421403213021 has 16 divisors (see below), whose sum is σ = 503077195008. Its totient is φ = 345131001600.

The previous prime is 421403213009. The next prime is 421403213051. The reversal of 421403213021 is 120312304124.

It is not a de Polignac number, because 421403213021 - 2¹⁸ = 421402950877 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421403213051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1239260 + ... + 1542261.

It is an arithmetic number, because the mean of its divisors is an integer number (31442324688).

Almost surely, 2^421403213021 is an apocalyptic number.

It is an amenable number.

421403213021 is a deficient number, since it is larger than the sum of its proper divisors (81673981987).

421403213021 is a wasteful number, since it uses less digits than its factorization.

421403213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2782492.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 421403213021 its reverse (120312304124), we get a palindrome (541715517145).

The spelling of 421403213021 in words is "four hundred twenty-one billion, four hundred three million, two hundred thirteen thousand, twenty-one".