221666533155 has 24 divisors (see below), whose sum is σ = 384517420560. Its totient is φ = 118131249600.

The previous prime is 221666533117. The next prime is 221666533159. The reversal of 221666533155 is 551335666122.

It is not a de Polignac number, because 221666533155 - 2¹⁶ = 221666467619 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 221666533155.

It is not an unprimeable number, because it can be changed into a prime (221666533159) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1834585 + ... + 1951674.

It is an arithmetic number, because the mean of its divisors is an integer number (16021559190).

Almost surely, 2^221666533155 is an apocalyptic number.

221666533155 is a deficient number, since it is larger than the sum of its proper divisors (162850887405).

221666533155 is a wasteful number, since it uses less digits than its factorization.

221666533155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3787571 (or 3787568 counting only the distinct ones).

The product of its digits is 972000, while the sum is 45.

The spelling of 221666533155 in words is "two hundred twenty-one billion, six hundred sixty-six million, five hundred thirty-three thousand, one hundred fifty-five".