221334665778 has 110 divisors (see below), whose sum is σ = 511833517899. Its totient is φ = 71784215928.

The previous prime is 221334665777. The next prime is 221334665801. The reversal of 221334665778 is 877566433122.

It is a happy number.

221334665778 is a `hidden beast` number, since 2 + 2 + 1 + 3 + 3 + 4 + 66 + 577 + 8 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 217905040809 + 3429624969 = 466803^2 + 58563^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=332667.

It is a Harshad number since it is a multiple of its sum of digits (54).

Its product of digits (10160640) is a multiple of the sum of its prime divisors (42).

It is not an unprimeable number, because it can be changed into a prime (221334665777) by changing a digit.

It is a polite number, since it can be written in 54 ways as a sum of consecutive naturals, for example, 5982017976 + ... + 5982018012.

Almost surely, 2^221334665778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221334665778

221334665778 is an abundant number, since it is smaller than the sum of its proper divisors (290498852121).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221334665778 is an frugal number, since it uses more digits than its factorization.

221334665778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 42 counting only the distinct ones).

The product of its digits is 10160640, while the sum is 54.

The spelling of 221334665778 in words is "two hundred twenty-one billion, three hundred thirty-four million, six hundred sixty-five thousand, seven hundred seventy-eight".