221561344 has 20 divisors (see below), whose sum is σ = 442690974. Its totient is φ = 110780416.

The previous prime is 221561321. The next prime is 221561381. The reversal of 221561344 is 443165122.

221561344 = T₁₂₁₅₂ + T₁₂₁₅₃ + T₁₂₁₅₄.

It can be written as a sum of positive squares in only one way, i.e., 127238400 + 94322944 = 11280^2 + 9712^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 215857 + ... + 216880.

Almost surely, 2^221561344 is an apocalyptic number.

221561344 is the 12154-th centered triangular number.

It is an amenable number.

221561344 is a deficient number, since it is larger than the sum of its proper divisors (221129630).

221561344 is an frugal number, since it uses more digits than its factorization.

221561344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432755 (or 432739 counting only the distinct ones).

The product of its digits is 5760, while the sum is 28.

The square root of 221561344 is about 14884.9368154521. The cubic root of 221561344 is about 605.1058203443.

The spelling of 221561344 in words is "two hundred twenty-one million, five hundred sixty-one thousand, three hundred forty-four".