21242131421 has 16 divisors (see below), whose sum is σ = 24917913600. Its totient is φ = 17730543600.

The previous prime is 21242131411. The next prime is 21242131441. The reversal of 21242131421 is 12413124212.

It is a de Polignac number, because none of the positive numbers 2^k-21242131421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242131411) 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, 96755 + ... + 227696.

It is an arithmetic number, because the mean of its divisors is an integer number (1557369600).

Almost surely, 2^21242131421 is an apocalyptic number.

It is an amenable number.

21242131421 is a deficient number, since it is larger than the sum of its proper divisors (3675782179).

21242131421 is a wasteful number, since it uses less digits than its factorization.

21242131421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324704.

The product of its digits is 768, while the sum is 23.

Adding to 21242131421 its reverse (12413124212), we get a palindrome (33655255633).

The spelling of 21242131421 in words is "twenty-one billion, two hundred forty-two million, one hundred thirty-one thousand, four hundred twenty-one".