21135661364 has 12 divisors (see below), whose sum is σ = 37005980004. Its totient is φ = 10562524224.

The previous prime is 21135661333. The next prime is 21135661373. The reversal of 21135661364 is 46316653112.

It can be written as a sum of positive squares in 2 ways, for example, as 14566558864 + 6569102500 = 120692^2 + 81050^2 .

It is a congruent number.

It is an unprimeable number.

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, 1317647 + ... + 1333590.

It is an arithmetic number, because the mean of its divisors is an integer number (3083831667).

Almost surely, 2^21135661364 is an apocalyptic number.

It is an amenable number.

21135661364 is a deficient number, since it is larger than the sum of its proper divisors (15870318640).

21135661364 is a wasteful number, since it uses less digits than its factorization.

21135661364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2653234 (or 2653232 counting only the distinct ones).

The product of its digits is 77760, while the sum is 38.

The spelling of 21135661364 in words is "twenty-one billion, one hundred thirty-five million, six hundred sixty-one thousand, three hundred sixty-four".