16661331 has 6 divisors (see below), whose sum is σ = 24066380. Its totient is φ = 11107548.

The previous prime is 16661321. The next prime is 16661363. The reversal of 16661331 is 13316661.

It is a happy number.

It is not a de Polignac number, because 16661331 - 2¹⁷ = 16530259 is a prime.

It is a super-2 number, since 2×16661331² = 555199901383122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16661295 and 16661304.

It is not an unprimeable number, because it can be changed into a prime (16661321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 925621 + ... + 925638.

Almost surely, 2^16661331 is an apocalyptic number.

16661331 is a deficient number, since it is larger than the sum of its proper divisors (7405049).

16661331 is a wasteful number, since it uses less digits than its factorization.

16661331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1851265 (or 1851262 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 16661331 is about 4081.8293692902. The cubic root of 16661331 is about 255.4092160772.

Adding to 16661331 its reverse (13316661), we get a palindrome (29977992).

The spelling of 16661331 in words is "sixteen million, six hundred sixty-one thousand, three hundred thirty-one".