221256648 has 36 divisors (see below), whose sum is σ = 599578785. Its totient is φ = 73710144.

The previous prime is 221256617. The next prime is 221256677. The reversal of 221256648 is 846652122.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

221256648 is a `hidden beast` number, since 2 + 2 + 1 + 2 + 5 + 6 + 648 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 147331044 + 73925604 = 12138^2 + 8598^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=10518.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 125340 + ... + 127092.

Almost surely, 2^221256648 is an apocalyptic number.

It is an amenable number.

221256648 is an abundant number, since it is smaller than the sum of its proper divisors (378322137).

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

221256648 is an equidigital number, since it uses as much as digits as its factorization.

221256648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3518 (or 1758 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 221256648 is about 14874.6982490402. The cubic root of 221256648 is about 604.8283081778.

The spelling of 221256648 in words is "two hundred twenty-one million, two hundred fifty-six thousand, six hundred forty-eight".