16615221 has 8 divisors (see below), whose sum is σ = 25318464. Its totient is φ = 9494400.

The previous prime is 16615217. The next prime is 16615229. The reversal of 16615221 is 12251661.

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

It is not a de Polignac number, because 16615221 - 2² = 16615217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16615191 and 16615200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16615229) 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, 395580 + ... + 395621.

It is an arithmetic number, because the mean of its divisors is an integer number (3164808).

Almost surely, 2^16615221 is an apocalyptic number.

It is an amenable number.

16615221 is a deficient number, since it is larger than the sum of its proper divisors (8703243).

16615221 is an equidigital number, since it uses as much as digits as its factorization.

16615221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 791211.

The product of its digits is 720, while the sum is 24.

The square root of 16615221 is about 4076.1772532607. The cubic root of 16615221 is about 255.1733845813.

Adding to 16615221 its reverse (12251661), we get a palindrome (28866882).

It can be divided in two parts, 16615 and 221, that added together give a triangular number (16836 = T₁₈₃).

The spelling of 16615221 in words is "sixteen million, six hundred fifteen thousand, two hundred twenty-one".