221564628 has 36 divisors (see below), whose sum is σ = 561188628. Its totient is φ = 73706880.

The previous prime is 221564597. The next prime is 221564641. The reversal of 221564628 is 826465122.

It is a happy number.

221564628 is a `hidden beast` number, since 2 + 2 + 1 + 5 + 646 + 2 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 74960964 + 146603664 = 8658^2 + 12108^2 .

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

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

It is a junction number, because it is equal to n+sod(n) for n = 221564592 and 221564601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12850 + ... + 24662.

It is an arithmetic number, because the mean of its divisors is an integer number (15588573).

Almost surely, 2^221564628 is an apocalyptic number.

It is an amenable number.

221564628 is an abundant number, since it is smaller than the sum of its proper divisors (339624000).

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

221564628 is a wasteful number, since it uses less digits than its factorization.

221564628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12344 (or 12339 counting only the distinct ones).

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

The square root of 221564628 is about 14885.0471279066. The cubic root of 221564628 is about 605.1088099718.

The spelling of 221564628 in words is "two hundred twenty-one million, five hundred sixty-four thousand, six hundred twenty-eight".