21017706511 has 2 divisors, whose sum is σ = 21017706512. Its totient is φ = 21017706510.

The previous prime is 21017706481. The next prime is 21017706533. The reversal of 21017706511 is 11560771012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21017706511 - 2¹³ = 21017698319 is a prime.

It is a super-3 number, since 3×21017706511³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21017706581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508853255 + 10508853256.

It is an arithmetic number, because the mean of its divisors is an integer number (10508853256).

Almost surely, 2^21017706511 is an apocalyptic number.

21017706511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21017706511 is an equidigital number, since it uses as much as digits as its factorization.

21017706511 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2940, while the sum is 31.

The spelling of 21017706511 in words is "twenty-one billion, seventeen million, seven hundred six thousand, five hundred eleven".