21253240034551 has 16 divisors (see below), whose sum is σ = 25154686909440. Its totient is φ = 17569495772640.

The previous prime is 21253240034531. The next prime is 21253240034561. The reversal of 21253240034551 is 15543004235212.

It is a happy number.

It is not a de Polignac number, because 21253240034551 - 2¹¹ = 21253240032503 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21253240034551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253240034531) 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, 57531295 + ... + 57899536.

It is an arithmetic number, because the mean of its divisors is an integer number (1572167931840).

Almost surely, 2^{21253240034551} is an apocalyptic number.

21253240034551 is a deficient number, since it is larger than the sum of its proper divisors (3901446874889).

21253240034551 is a wasteful number, since it uses less digits than its factorization.

21253240034551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115431774.

The product of its (nonzero) digits is 144000, while the sum is 37.

Adding to 21253240034551 its reverse (15543004235212), we get a palindrome (36796244269763).

The spelling of 21253240034551 in words is "twenty-one trillion, two hundred fifty-three billion, two hundred forty million, thirty-four thousand, five hundred fifty-one".