221565644 has 6 divisors (see below), whose sum is σ = 387739884. Its totient is φ = 110782820.

The previous prime is 221565629. The next prime is 221565689. The reversal of 221565644 is 446565122.

221565644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221565644² = 98182669202269472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27695702 + ... + 27695709.

It is an arithmetic number, because the mean of its divisors is an integer number (64623314).

Almost surely, 2^221565644 is an apocalyptic number.

It is an amenable number.

221565644 is a deficient number, since it is larger than the sum of its proper divisors (166174240).

221565644 is a wasteful number, since it uses less digits than its factorization.

221565644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55391415 (or 55391413 counting only the distinct ones).

The product of its digits is 57600, while the sum is 35.

The square root of 221565644 is about 14885.0812560765. The cubic root of 221565644 is about 605.1097348933.

The spelling of 221565644 in words is "two hundred twenty-one million, five hundred sixty-five thousand, six hundred forty-four".