21655420653610 has 16 divisors (see below), whose sum is σ = 38980178937000. Its totient is φ = 8662074536896.

The previous prime is 21655420653571. The next prime is 21655420653667. The reversal of 21655420653610 is 1635602455612.

It can be written as a sum of positive squares in 4 ways, for example, as 5361628239361 + 16293792414249 = 2315519^2 + 4036557^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10741285 + ... + 12597064.

Almost surely, 2^{21655420653610} is an apocalyptic number.

21655420653610 is a deficient number, since it is larger than the sum of its proper divisors (17324758283390).

21655420653610 is a wasteful number, since it uses less digits than its factorization.

21655420653610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23431145.

The product of its (nonzero) digits is 1296000, while the sum is 46.

The spelling of 21655420653610 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred twenty million, six hundred fifty-three thousand, six hundred ten".