16311456521 has 4 divisors (see below), whose sum is σ = 16313875152. Its totient is φ = 16309037892.

The previous prime is 16311456517. The next prime is 16311456563. The reversal of 16311456521 is 12565411361.

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 16311456521 - 2² = 16311456517 is a prime.

It is a super-2 number, since 2×16311456521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16311450521) 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, 1199171 + ... + 1212696.

It is an arithmetic number, because the mean of its divisors is an integer number (4078468788).

Almost surely, 2^16311456521 is an apocalyptic number.

It is an amenable number.

16311456521 is a deficient number, since it is larger than the sum of its proper divisors (2418631).

16311456521 is an equidigital number, since it uses as much as digits as its factorization.

16311456521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2418630.

The product of its digits is 21600, while the sum is 35.

Adding to 16311456521 its reverse (12565411361), we get a palindrome (28876867882).

The spelling of 16311456521 in words is "sixteen billion, three hundred eleven million, four hundred fifty-six thousand, five hundred twenty-one".