21125405535 has 32 divisors (see below), whose sum is σ = 36446639040. Its totient is φ = 10387074048.

The previous prime is 21125405527. The next prime is 21125405537. The reversal of 21125405535 is 53550452112.

It is not a de Polignac number, because 21125405535 - 2³ = 21125405527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21125405496 and 21125405505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125405537) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87451 + ... + 223379.

It is an arithmetic number, because the mean of its divisors is an integer number (1138957470).

Almost surely, 2^21125405535 is an apocalyptic number.

21125405535 is a deficient number, since it is larger than the sum of its proper divisors (15321233505).

21125405535 is a wasteful number, since it uses less digits than its factorization.

21125405535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136747.

The product of its (nonzero) digits is 30000, while the sum is 33.

Adding to 21125405535 its reverse (53550452112), we get a palindrome (74675857647).

The spelling of 21125405535 in words is "twenty-one billion, one hundred twenty-five million, four hundred five thousand, five hundred thirty-five".