21201097912949 has 2 divisors, whose sum is σ = 21201097912950. Its totient is φ = 21201097912948.

The previous prime is 21201097912913. The next prime is 21201097912961. The reversal of 21201097912949 is 94921979010212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10974597460849 + 10226500452100 = 3312793^2 + 3197890^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201097912949 - 2²⁸ = 21200829477493 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201097912894 and 21201097912903.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201097962949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600548956474 + 10600548956475.

It is an arithmetic number, because the mean of its divisors is an integer number (10600548956475).

Almost surely, 2^{21201097912949} is an apocalyptic number.

It is an amenable number.

21201097912949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201097912949 is an equidigital number, since it uses as much as digits as its factorization.

21201097912949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 56.

The spelling of 21201097912949 in words is "twenty-one trillion, two hundred one billion, ninety-seven million, nine hundred twelve thousand, nine hundred forty-nine".