221107509 has 32 divisors (see below), whose sum is σ = 375840000. Its totient is φ = 125848512.

The previous prime is 221107489. The next prime is 221107577. The reversal of 221107509 is 905701122.

It is not a de Polignac number, because 221107509 - 2⁵ = 221107477 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221107589) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48667 + ... + 53015.

It is an arithmetic number, because the mean of its divisors is an integer number (11745000).

Almost surely, 2^221107509 is an apocalyptic number.

It is an amenable number.

221107509 is a deficient number, since it is larger than the sum of its proper divisors (154732491).

221107509 is a wasteful number, since it uses less digits than its factorization.

221107509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4634 (or 4628 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 221107509 is about 14869.6842266405. The cubic root of 221107509 is about 604.6923819208.

The spelling of 221107509 in words is "two hundred twenty-one million, one hundred seven thousand, five hundred nine".