21011211017 has 2 divisors, whose sum is σ = 21011211018. Its totient is φ = 21011211016.

The previous prime is 21011210963. The next prime is 21011211029. The reversal of 21011211017 is 71011211012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17686074121 + 3325136896 = 132989^2 + 57664^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011211017 - 2¹² = 21011206921 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21011210986 and 21011211004.

It is not a weakly prime, because it can be changed into another prime (21011211077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505605508 + 10505605509.

It is an arithmetic number, because the mean of its divisors is an integer number (10505605509).

Almost surely, 2^21011211017 is an apocalyptic number.

It is an amenable number.

21011211017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011211017 is an equidigital number, since it uses as much as digits as its factorization.

21011211017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28, while the sum is 17.

Adding to 21011211017 its reverse (71011211012), we get a palindrome (92022422029).

The spelling of 21011211017 in words is "twenty-one billion, eleven million, two hundred eleven thousand, seventeen".