21012111097 has 2 divisors, whose sum is σ = 21012111098. Its totient is φ = 21012111096.

The previous prime is 21012111089. The next prime is 21012111149. The reversal of 21012111097 is 79011121012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12277526416 + 8734584681 = 110804^2 + 93459^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012111097 - 2³ = 21012111089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012111017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506055548 + 10506055549.

It is an arithmetic number, because the mean of its divisors is an integer number (10506055549).

Almost surely, 2^21012111097 is an apocalyptic number.

It is an amenable number.

21012111097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012111097 is an equidigital number, since it uses as much as digits as its factorization.

21012111097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 252, while the sum is 25.

The spelling of 21012111097 in words is "twenty-one billion, twelve million, one hundred eleven thousand, ninety-seven".