16451779509 has 40 divisors (see below), whose sum is σ = 26937678240. Its totient is φ = 9923407200.

The previous prime is 16451779499. The next prime is 16451779511. The reversal of 16451779509 is 90597715461.

16451779509 is a `hidden beast` number, since 1 + 6 + 4 + 517 + 79 + 50 + 9 = 666.

It is not a de Polignac number, because 16451779509 - 2¹² = 16451775413 is a prime.

It is a super-2 number, since 2×16451779509² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16451779559) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 144247 + ... + 231755.

It is an arithmetic number, because the mean of its divisors is an integer number (673441956).

Almost surely, 2^16451779509 is an apocalyptic number.

It is an amenable number.

16451779509 is a deficient number, since it is larger than the sum of its proper divisors (10485898731).

16451779509 is a wasteful number, since it uses less digits than its factorization.

16451779509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87743 (or 87734 counting only the distinct ones).

The product of its (nonzero) digits is 2381400, while the sum is 54.

The spelling of 16451779509 in words is "sixteen billion, four hundred fifty-one million, seven hundred seventy-nine thousand, five hundred nine".