21252561551129 has 2 divisors, whose sum is σ = 21252561551130. Its totient is φ = 21252561551128.

The previous prime is 21252561551093. The next prime is 21252561551201. The reversal of 21252561551129 is 92115516525212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14737713694729 + 6514847856400 = 3838973^2 + 2552420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21252561551129 is a prime.

It is not a weakly prime, because it can be changed into another prime (21252561551329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626280775564 + 10626280775565.

It is an arithmetic number, because the mean of its divisors is an integer number (10626280775565).

Almost surely, 2^{21252561551129} is an apocalyptic number.

It is an amenable number.

21252561551129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252561551129 is an equidigital number, since it uses as much as digits as its factorization.

21252561551129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540000, while the sum is 47.

The spelling of 21252561551129 in words is "twenty-one trillion, two hundred fifty-two billion, five hundred sixty-one million, five hundred fifty-one thousand, one hundred twenty-nine".