16581309612 has 48 divisors (see below), whose sum is σ = 44839613952. Its totient is φ = 4670789760.

The previous prime is 16581309599. The next prime is 16581309623. The reversal of 16581309612 is 21690318561.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1384153 + ... + 1396080.

It is an arithmetic number, because the mean of its divisors is an integer number (934158624).

Almost surely, 2^16581309612 is an apocalyptic number.

16581309612 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

16581309612 is an abundant number, since it is smaller than the sum of its proper divisors (28258304340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16581309612 is a wasteful number, since it uses less digits than its factorization.

16581309612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780318 (or 2780316 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The spelling of 16581309612 in words is "sixteen billion, five hundred eighty-one million, three hundred nine thousand, six hundred twelve".