21011323117 has 2 divisors, whose sum is σ = 21011323118. Its totient is φ = 21011323116.

The previous prime is 21011323007. The next prime is 21011323121. The reversal of 21011323117 is 71132311012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16711767076 + 4299556041 = 129274^2 + 65571^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011323117 - 2¹⁹ = 21010798829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011326117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505661558 + 10505661559.

It is an arithmetic number, because the mean of its divisors is an integer number (10505661559).

Almost surely, 2^21011323117 is an apocalyptic number.

It is an amenable number.

21011323117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011323117 is an equidigital number, since it uses as much as digits as its factorization.

21011323117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 22.

Adding to 21011323117 its reverse (71132311012), we get a palindrome (92143634129).

The spelling of 21011323117 in words is "twenty-one billion, eleven million, three hundred twenty-three thousand, one hundred seventeen".