21051232342551 has 36 divisors (see below), whose sum is σ = 31257662897448. Its totient is φ = 13647502831872.

The previous prime is 21051232342541. The next prime is 21051232342559. The reversal of 21051232342551 is 15524323215012.

21051232342551 is a `hidden beast` number, since 2 + 1 + 0 + 51 + 23 + 2 + 34 + 2 + 551 = 666.

It is not a de Polignac number, because 21051232342551 - 2¹³ = 21051232334359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051232342559) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4362700 + ... + 7818926.

It is an arithmetic number, because the mean of its divisors is an integer number (868268413818).

Almost surely, 2^{21051232342551} is an apocalyptic number.

21051232342551 is a deficient number, since it is larger than the sum of its proper divisors (10206430554897).

21051232342551 is a wasteful number, since it uses less digits than its factorization.

21051232342551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3456512 (or 3456396 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

Adding to 21051232342551 its reverse (15524323215012), we get a palindrome (36575555557563).

The spelling of 21051232342551 in words is "twenty-one trillion, fifty-one billion, two hundred thirty-two million, three hundred forty-two thousand, five hundred fifty-one".