21616231664656 has 10 divisors (see below), whose sum is σ = 41881448850302. Its totient is φ = 10808115832320.

The previous prime is 21616231664647. The next prime is 21616231664669. The reversal of 21616231664656 is 65646613261612.

It can be written as a sum of positive squares in only one way, i.e., 21118473194256 + 497758470400 = 4595484^2 + 705520^2 .

It is a super-2 number, since 2×21616231664656² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21616231664597 and 21616231664606.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675507239505 + ... + 675507239536.

Almost surely, 2^{21616231664656} is an apocalyptic number.

It is an amenable number.

21616231664656 is a deficient number, since it is larger than the sum of its proper divisors (20265217185646).

21616231664656 is a wasteful number, since it uses less digits than its factorization.

21616231664656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1351014479049 (or 1351014479043 counting only the distinct ones).

The product of its digits is 11197440, while the sum is 55.

The spelling of 21616231664656 in words is "twenty-one trillion, six hundred sixteen billion, two hundred thirty-one million, six hundred sixty-four thousand, six hundred fifty-six".