21234213352551 has 4 divisors (see below), whose sum is σ = 28312284470072. Its totient is φ = 14156142235032.

The previous prime is 21234213352529. The next prime is 21234213352619. The reversal of 21234213352551 is 15525331243212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21234213352551 - 2²⁵ = 21234179798119 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 (21234213312551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3539035558756 + ... + 3539035558761.

It is an arithmetic number, because the mean of its divisors is an integer number (7078071117518).

Almost surely, 2^{21234213352551} is an apocalyptic number.

21234213352551 is a deficient number, since it is larger than the sum of its proper divisors (7078071117521).

21234213352551 is an equidigital number, since it uses as much as digits as its factorization.

21234213352551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7078071117520.

The product of its digits is 216000, while the sum is 39.

Adding to 21234213352551 its reverse (15525331243212), we get a palindrome (36759544595763).

The spelling of 21234213352551 in words is "twenty-one trillion, two hundred thirty-four billion, two hundred thirteen million, three hundred fifty-two thousand, five hundred fifty-one".