16399387 has 4 divisors (see below), whose sum is σ = 16509600. Its totient is φ = 16289176.

The previous prime is 16399363. The next prime is 16399393. The reversal of 16399387 is 78399361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78399361 = 8747 ⋅8963.

It is a cyclic number.

It is not a de Polignac number, because 16399387 - 2⁷ = 16399259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16399307) 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, 54883 + ... + 55180.

It is an arithmetic number, because the mean of its divisors is an integer number (4127400).

Almost surely, 2^16399387 is an apocalyptic number.

16399387 is a deficient number, since it is larger than the sum of its proper divisors (110213).

16399387 is a wasteful number, since it uses less digits than its factorization.

16399387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110212.

The product of its digits is 244944, while the sum is 46.

The square root of 16399387 is about 4049.6156607757. The cubic root of 16399387 is about 254.0636530077.

It can be divided in two parts, 1639 and 9387, that added together give a triangular number (11026 = T₁₄₈).

The spelling of 16399387 in words is "sixteen million, three hundred ninety-nine thousand, three hundred eighty-seven".