21135702664 has 8 divisors (see below), whose sum is σ = 39629442510. Its totient is φ = 10567851328.

The previous prime is 21135702589. The next prime is 21135702713. The reversal of 21135702664 is 46620753112.

It can be written as a sum of positive squares in only one way, i.e., 20280608100 + 855094564 = 142410^2 + 29242^2 .

It is a tau number, because it is divible by the number of its divisors (8).

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 as a sum of consecutive naturals, namely, 1320981409 + ... + 1320981424.

Almost surely, 2^21135702664 is an apocalyptic number.

It is an amenable number.

21135702664 is a deficient number, since it is larger than the sum of its proper divisors (18493739846).

21135702664 is a wasteful number, since it uses less digits than its factorization.

21135702664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2641962839 (or 2641962835 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 37.

The spelling of 21135702664 in words is "twenty-one billion, one hundred thirty-five million, seven hundred two thousand, six hundred sixty-four".