21135645352 has 16 divisors (see below), whose sum is σ = 41960472660. Its totient is φ = 9946185984.

The previous prime is 21135645337. The next prime is 21135645359. The reversal of 21135645352 is 25354653112.

It can be written as a sum of positive squares in 2 ways, for example, as 19770047236 + 1365598116 = 140606^2 + 36954^2 .

It is not an unprimeable number, because it can be changed into a prime (21135645359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77704443 + ... + 77704714.

Almost surely, 2^21135645352 is an apocalyptic number.

It is an amenable number.

21135645352 is a deficient number, since it is larger than the sum of its proper divisors (20824827308).

21135645352 is a wasteful number, since it uses less digits than its factorization.

21135645352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155409180 (or 155409176 counting only the distinct ones).

The product of its digits is 108000, while the sum is 37.

It can be divided in two parts, 2113 and 5645352, that added together give a palindrome (5647465).

The spelling of 21135645352 in words is "twenty-one billion, one hundred thirty-five million, six hundred forty-five thousand, three hundred fifty-two".