21704115211 has 2 divisors, whose sum is σ = 21704115212. Its totient is φ = 21704115210.

The previous prime is 21704115193. The next prime is 21704115221. The reversal of 21704115211 is 11251140712.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21704115211 - 2²¹ = 21702018059 is a prime.

It is not a weakly prime, because it can be changed into another prime (21704115221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10852057605 + 10852057606.

It is an arithmetic number, because the mean of its divisors is an integer number (10852057606).

Almost surely, 2^21704115211 is an apocalyptic number.

21704115211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21704115211 is an equidigital number, since it uses as much as digits as its factorization.

21704115211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 25.

Adding to 21704115211 its reverse (11251140712), we get a palindrome (32955255923).

The spelling of 21704115211 in words is "twenty-one billion, seven hundred four million, one hundred fifteen thousand, two hundred eleven".