21461609236 has 12 divisors (see below), whose sum is σ = 37797039028. Its totient is φ = 10662455232.

The previous prime is 21461609171. The next prime is 21461609243. The reversal of 21461609236 is 63290616412.

It can be written as a sum of positive squares in 2 ways, for example, as 16073168400 + 5388440836 = 126780^2 + 73406^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17086641 + ... + 17087896.

Almost surely, 2^21461609236 is an apocalyptic number.

It is an amenable number.

21461609236 is a deficient number, since it is larger than the sum of its proper divisors (16335429792).

21461609236 is a wasteful number, since it uses less digits than its factorization.

21461609236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34174698 (or 34174696 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 40.

The spelling of 21461609236 in words is "twenty-one billion, four hundred sixty-one million, six hundred nine thousand, two hundred thirty-six".