21542071097 has 2 divisors, whose sum is σ = 21542071098. Its totient is φ = 21542071096.

The previous prime is 21542071093. The next prime is 21542071099. The reversal of 21542071097 is 79017024512.

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., 21539671696 + 2399401 = 146764^2 + 1549^2 .

It is a cyclic number.

It is not a de Polignac number, because 21542071097 - 2² = 21542071093 is a prime.

Together with 21542071099, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21542071097.

It is not a weakly prime, because it can be changed into another prime (21542071093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10771035548 + 10771035549.

It is an arithmetic number, because the mean of its divisors is an integer number (10771035549).

Almost surely, 2^21542071097 is an apocalyptic number.

It is an amenable number.

21542071097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21542071097 is an equidigital number, since it uses as much as digits as its factorization.

21542071097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 38.

The spelling of 21542071097 in words is "twenty-one billion, five hundred forty-two million, seventy-one thousand, ninety-seven".