16644399660 has 144 divisors (see below), whose sum is σ = 57734703936. Its totient is φ = 3802185216.

The previous prime is 16644399613. The next prime is 16644399683. The reversal of 16644399660 is 6699344661.

16644399660 is a `hidden beast` number, since 1 + 6 + 64 + 439 + 96 + 60 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 16644399597 and 16644399606.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3118354 + ... + 3123686.

It is an arithmetic number, because the mean of its divisors is an integer number (400935444).

Almost surely, 2^16644399660 is an apocalyptic number.

16644399660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16644399660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28867351968).

16644399660 is an abundant number, since it is smaller than the sum of its proper divisors (41090304276).

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

16644399660 is a wasteful number, since it uses less digits than its factorization.

16644399660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7832 (or 7827 counting only the distinct ones).

The product of its (nonzero) digits is 5038848, while the sum is 54.

The spelling of 16644399660 in words is "sixteen billion, six hundred forty-four million, three hundred ninety-nine thousand, six hundred sixty".