16405398991 has 8 divisors (see below), whose sum is σ = 17121844224. Its totient is φ = 15689217720.

The previous prime is 16405398983. The next prime is 16405399027. The reversal of 16405398991 is 19989350461.

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

It is a cyclic number.

It is not a de Polignac number, because 16405398991 - 2³ = 16405398983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16405398941) 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, 66726 + ... + 193036.

It is an arithmetic number, because the mean of its divisors is an integer number (2140230528).

Almost surely, 2^16405398991 is an apocalyptic number.

16405398991 is a deficient number, since it is larger than the sum of its proper divisors (716445233).

16405398991 is a wasteful number, since it uses less digits than its factorization.

16405398991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131981.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 16405398991 in words is "sixteen billion, four hundred five million, three hundred ninety-eight thousand, nine hundred ninety-one".