21531345045251 has 2 divisors, whose sum is σ = 21531345045252. Its totient is φ = 21531345045250.

The previous prime is 21531345045247. The next prime is 21531345045281. The reversal of 21531345045251 is 15254054313512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21531345045251 - 2² = 21531345045247 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21531345045199 and 21531345045208.

It is not a weakly prime, because it can be changed into another prime (21531345045281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765672522625 + 10765672522626.

It is an arithmetic number, because the mean of its divisors is an integer number (10765672522626).

Almost surely, 2^{21531345045251} is an apocalyptic number.

21531345045251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21531345045251 is an equidigital number, since it uses as much as digits as its factorization.

21531345045251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360000, while the sum is 41.

Adding to 21531345045251 its reverse (15254054313512), we get a palindrome (36785399358763).

The spelling of 21531345045251 in words is "twenty-one trillion, five hundred thirty-one billion, three hundred forty-five million, forty-five thousand, two hundred fifty-one".