21585858511 has 16 divisors (see below), whose sum is σ = 26126819136. Its totient is φ = 17409724416.

The previous prime is 21585858509. The next prime is 21585858529. The reversal of 21585858511 is 11585858512.

It is not a de Polignac number, because 21585858511 - 2¹ = 21585858509 is a prime.

It is a super-2 number, since 2×21585858511² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21585858311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 554395 + ... + 592051.

It is an arithmetic number, because the mean of its divisors is an integer number (1632926196).

Almost surely, 2^21585858511 is an apocalyptic number.

21585858511 is a deficient number, since it is larger than the sum of its proper divisors (4540960625).

21585858511 is a wasteful number, since it uses less digits than its factorization.

21585858511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42498.

The product of its digits is 640000, while the sum is 49.

Subtracting from 21585858511 its reverse (11585858512), we obtain a palindrome (9999999999).

The spelling of 21585858511 in words is "twenty-one billion, five hundred eighty-five million, eight hundred fifty-eight thousand, five hundred eleven".