21665734952 has 8 divisors (see below), whose sum is σ = 40623253050. Its totient is φ = 10832867472.

The previous prime is 21665734907. The next prime is 21665734969. The reversal of 21665734952 is 25943756612.

It can be written as a sum of positive squares in only one way, i.e., 20367285796 + 1298449156 = 142714^2 + 36034^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21665734952.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1354108427 + ... + 1354108442.

Almost surely, 2^21665734952 is an apocalyptic number.

It is an amenable number.

21665734952 is a deficient number, since it is larger than the sum of its proper divisors (18957518098).

21665734952 is a wasteful number, since it uses less digits than its factorization.

21665734952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2708216875 (or 2708216871 counting only the distinct ones).

The product of its digits is 2721600, while the sum is 50.

The spelling of 21665734952 in words is "twenty-one billion, six hundred sixty-five million, seven hundred thirty-four thousand, nine hundred fifty-two".