221709147 has 24 divisors (see below), whose sum is σ = 336149520. Its totient is φ = 129729600.

The previous prime is 221709139. The next prime is 221709151. The reversal of 221709147 is 741907122.

It is not a de Polignac number, because 221709147 - 2³ = 221709139 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (221709127) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4 + ... + 21057.

It is an arithmetic number, because the mean of its divisors is an integer number (14006230).

Almost surely, 2^221709147 is an apocalyptic number.

221709147 is a deficient number, since it is larger than the sum of its proper divisors (114440373).

221709147 is a wasteful number, since it uses less digits than its factorization.

221709147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21115 (or 21104 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 33.

The square root of 221709147 is about 14889.9008391594. The cubic root of 221709147 is about 605.2403452780.

The spelling of 221709147 in words is "two hundred twenty-one million, seven hundred nine thousand, one hundred forty-seven".