21252561551201 has 2 divisors, whose sum is σ = 21252561551202. Its totient is φ = 21252561551200.

The previous prime is 21252561551129. The next prime is 21252561551227. The reversal of 21252561551201 is 10215516525212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12462848636176 + 8789712915025 = 3530276^2 + 2964745^2 .

It is a cyclic number.

It is not a de Polignac number, because 21252561551201 - 2¹⁰ = 21252561550177 is a prime.

It is not a weakly prime, because it can be changed into another prime (21252561551231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626280775600 + 10626280775601.

It is an arithmetic number, because the mean of its divisors is an integer number (10626280775601).

Almost surely, 2^{21252561551201} is an apocalyptic number.

It is an amenable number.

21252561551201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252561551201 is an equidigital number, since it uses as much as digits as its factorization.

21252561551201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60000, while the sum is 38.

The spelling of 21252561551201 in words is "twenty-one trillion, two hundred fifty-two billion, five hundred sixty-one million, five hundred fifty-one thousand, two hundred one".