21521543026135 has 16 divisors (see below), whose sum is σ = 26786153917440. Its totient is φ = 16580133149440.

The previous prime is 21521543026127. The next prime is 21521543026183. The reversal of 21521543026135 is 53162034512512.

It is not a de Polignac number, because 21521543026135 - 2³ = 21521543026127 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 193710046 + ... + 193821115.

It is an arithmetic number, because the mean of its divisors is an integer number (1674134619840).

Almost surely, 2^{21521543026135} is an apocalyptic number.

21521543026135 is a deficient number, since it is larger than the sum of its proper divisors (5264610891305).

21521543026135 is a wasteful number, since it uses less digits than its factorization.

21521543026135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387531578.

The product of its (nonzero) digits is 216000, while the sum is 40.

Adding to 21521543026135 its reverse (53162034512512), we get a palindrome (74683577538647).

The spelling of 21521543026135 in words is "twenty-one trillion, five hundred twenty-one billion, five hundred forty-three million, twenty-six thousand, one hundred thirty-five".