21655362666145 has 16 divisors (see below), whose sum is σ = 27985580335440. Its totient is φ = 15991544669184.

The previous prime is 21655362666071. The next prime is 21655362666163. The reversal of 21655362666145 is 54166626355612.

It can be written as a sum of positive squares in 8 ways, for example, as 1416845037969 + 20238517628176 = 1190313^2 + 4498724^2 .

It is a cyclic number.

It is not a de Polignac number, because 21655362666145 - 2⁷ = 21655362666017 is a prime.

It is a super-2 number, since 2×21655362666145² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21655362666145.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9342357 + ... + 11427613.

It is an arithmetic number, because the mean of its divisors is an integer number (1749098770965).

Almost surely, 2^{21655362666145} is an apocalyptic number.

It is an amenable number.

21655362666145 is a deficient number, since it is larger than the sum of its proper divisors (6330217669295).

21655362666145 is a wasteful number, since it uses less digits than its factorization.

21655362666145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2245044.

The product of its digits is 46656000, while the sum is 58.

The spelling of 21655362666145 in words is "twenty-one trillion, six hundred fifty-five billion, three hundred sixty-two million, six hundred sixty-six thousand, one hundred forty-five".