21009398127201 has 315 divisors, whose sum is σ = 36824966777235. Its totient is φ = 11979699573600.

The previous prime is 21009398127187. The next prime is 21009398127257. The reversal of 21009398127201 is 10272189390012.

The square root of 21009398127201 is 4583601.

It is a perfect power (a square), and thus also a powerful number.

21009398127201 is a `hidden beast` number, since 210 + 0 + 9 + 398 + 1 + 27 + 20 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 683186555601 + 20326211571600 = 826551^2 + 4508460^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21009398127201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21009398127901) by changing a digit.

It is a polite number, since it can be written in 314 ways as a sum of consecutive naturals, for example, 344416362711 + ... + 344416362771.

Almost surely, 2^{21009398127201} is an apocalyptic number.

21009398127201 is the 4583601-st square number.

21009398127201 is the 2291801-st centered octagonal number.

It is an amenable number.

21009398127201 is a deficient number, since it is larger than the sum of its proper divisors (15815568650034).

21009398127201 is an frugal number, since it uses more digits than its factorization.

21009398127201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The spelling of 21009398127201 in words is "twenty-one trillion, nine billion, three hundred ninety-eight million, one hundred twenty-seven thousand, two hundred one".