20161216401 has 4 divisors (see below), whose sum is σ = 26881621872. Its totient is φ = 13440810932.

The previous prime is 20161216393. The next prime is 20161216477. The reversal of 20161216401 is 10461216102.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 20161216401 - 2³ = 20161216393 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20161214401) 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, 3360202731 + ... + 3360202736.

It is an arithmetic number, because the mean of its divisors is an integer number (6720405468).

Almost surely, 2^20161216401 is an apocalyptic number.

It is an amenable number.

20161216401 is a deficient number, since it is larger than the sum of its proper divisors (6720405471).

20161216401 is an equidigital number, since it uses as much as digits as its factorization.

20161216401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6720405470.

The product of its (nonzero) digits is 576, while the sum is 24.

The spelling of 20161216401 in words is "twenty billion, one hundred sixty-one million, two hundred sixteen thousand, four hundred one".