221666155110545 has 8 divisors (see below), whose sum is σ = 266008510561896. Its totient is φ = 177326841135616.

The previous prime is 221666155110503. The next prime is 221666155110607. The reversal of 221666155110545 is 545011551666122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1861453651201 + 219804701459344 = 1364351^2 + 14825812^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221666155110545 - 2³⁰ = 221665081368721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221666155110493 and 221666155110502.

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, 760208762 + ... + 760500291.

It is an arithmetic number, because the mean of its divisors is an integer number (33251063820237).

Almost surely, 2^{221666155110545} is an apocalyptic number.

It is an amenable number.

221666155110545 is a deficient number, since it is larger than the sum of its proper divisors (44342355451351).

221666155110545 is a wasteful number, since it uses less digits than its factorization.

221666155110545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520738211.

The product of its (nonzero) digits is 2160000, while the sum is 50.

The spelling of 221666155110545 in words is "two hundred twenty-one trillion, six hundred sixty-six billion, one hundred fifty-five million, one hundred ten thousand, five hundred forty-five".