21255616135 has 16 divisors (see below), whose sum is σ = 27501606720. Its totient is φ = 15677706240.

The previous prime is 21255616121. The next prime is 21255616157. The reversal of 21255616135 is 53161655212.

It is a happy number.

It is not a de Polignac number, because 21255616135 - 2⁷ = 21255616007 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21255616094 and 21255616103.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140346 + ... + 249415.

It is an arithmetic number, because the mean of its divisors is an integer number (1718850420).

Almost surely, 2^21255616135 is an apocalyptic number.

21255616135 is a deficient number, since it is larger than the sum of its proper divisors (6245990585).

21255616135 is a wasteful number, since it uses less digits than its factorization.

21255616135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390618.

The product of its digits is 54000, while the sum is 37.

The spelling of 21255616135 in words is "twenty-one billion, two hundred fifty-five million, six hundred sixteen thousand, one hundred thirty-five".