21240421351 has 8 divisors (see below), whose sum is σ = 21806391024. Its totient is φ = 20680570560.

The previous prime is 21240421331. The next prime is 21240421361. The reversal of 21240421351 is 15312404212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21240421351 - 2²⁷ = 21106203623 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 (21240421331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1522686 + ... + 1536571.

It is an arithmetic number, because the mean of its divisors is an integer number (2725798878).

Almost surely, 2^21240421351 is an apocalyptic number.

21240421351 is a deficient number, since it is larger than the sum of its proper divisors (565969673).

21240421351 is a wasteful number, since it uses less digits than its factorization.

21240421351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3059441.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21240421351 its reverse (15312404212), we get a palindrome (36552825563).

The spelling of 21240421351 in words is "twenty-one billion, two hundred forty million, four hundred twenty-one thousand, three hundred fifty-one".