16218397 has 4 divisors (see below), whose sum is σ = 17465980. Its totient is φ = 14970816.

The previous prime is 16218373. The next prime is 16218401. The reversal of 16218397 is 79381261.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9771876 + 6446521 = 3126^2 + 2539^2 .

It is a cyclic number.

It is not a de Polignac number, because 16218397 - 2⁷ = 16218269 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16218347) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 623772 + ... + 623797.

It is an arithmetic number, because the mean of its divisors is an integer number (4366495).

Almost surely, 2^16218397 is an apocalyptic number.

It is an amenable number.

16218397 is a deficient number, since it is larger than the sum of its proper divisors (1247583).

16218397 is a wasteful number, since it uses less digits than its factorization.

16218397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247582.

The product of its digits is 18144, while the sum is 37.

The square root of 16218397 is about 4027.2070967359. The cubic root of 16218397 is about 253.1255450275.

The spelling of 16218397 in words is "sixteen million, two hundred eighteen thousand, three hundred ninety-seven".