21020541097 has 2 divisors, whose sum is σ = 21020541098. Its totient is φ = 21020541096.

The previous prime is 21020541079. The next prime is 21020541103. The reversal of 21020541097 is 79014502012.

Together with previous prime (21020541079) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18831798441 + 2188742656 = 137229^2 + 46784^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020541097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21020541037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510270548 + 10510270549.

It is an arithmetic number, because the mean of its divisors is an integer number (10510270549).

Almost surely, 2^21020541097 is an apocalyptic number.

It is an amenable number.

21020541097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020541097 is an equidigital number, since it uses as much as digits as its factorization.

21020541097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 31.

The spelling of 21020541097 in words is "twenty-one billion, twenty million, five hundred forty-one thousand, ninety-seven".