221665245 has 8 divisors (see below), whose sum is σ = 354664416. Its totient is φ = 118221456.

The previous prime is 221665243. The next prime is 221665247. The reversal of 221665245 is 542566122.

It is an interprime number because it is at equal distance from previous prime (221665243) and next prime (221665247).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221665245 - 2¹ = 221665243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221665243) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7388827 + ... + 7388856.

It is an arithmetic number, because the mean of its divisors is an integer number (44333052).

Almost surely, 2^221665245 is an apocalyptic number.

It is an amenable number.

221665245 is a deficient number, since it is larger than the sum of its proper divisors (132999171).

221665245 is a wasteful number, since it uses less digits than its factorization.

221665245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14777691.

The product of its digits is 28800, while the sum is 33.

The square root of 221665245 is about 14888.4265454748. The cubic root of 221665245 is about 605.2003935123.

The spelling of 221665245 in words is "two hundred twenty-one million, six hundred sixty-five thousand, two hundred forty-five".