16401409 has 4 divisors (see below), whose sum is σ = 16409520. Its totient is φ = 16393300.

The previous prime is 16401403. The next prime is 16401419. The reversal of 16401409 is 90410461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90410461 = 2861 ⋅31601.

It is a cyclic number.

It is not a de Polignac number, because 16401409 - 2⁵ = 16401377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16401403) 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, 1722 + ... + 5980.

It is an arithmetic number, because the mean of its divisors is an integer number (4102380).

Almost surely, 2^16401409 is an apocalyptic number.

It is an amenable number.

16401409 is a deficient number, since it is larger than the sum of its proper divisors (8111).

16401409 is an equidigital number, since it uses as much as digits as its factorization.

16401409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8110.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 16401409 is about 4049.8653064022. The cubic root of 16401409 is about 254.0740943654.

The spelling of 16401409 in words is "sixteen million, four hundred one thousand, four hundred nine".