16389440640 has 256 divisors, whose sum is σ = 58204137600. Its totient is φ = 4358615040.

The previous prime is 16389440629. The next prime is 16389440663. The reversal of 16389440640 is 4604498361.

16389440640 is a `hidden beast` number, since 1 + 638 + 9 + 4 + 4 + 0 + 6 + 4 + 0 = 666.

It is a super-2 number, since 2×16389440640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7653970 + ... + 7656110.

Almost surely, 2^16389440640 is an apocalyptic number.

16389440640 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 16389440640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29102068800).

16389440640 is an abundant number, since it is smaller than the sum of its proper divisors (41814696960).

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

16389440640 is a wasteful number, since it uses less digits than its factorization.

16389440640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2612 (or 2594 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 16389440640 in words is "sixteen billion, three hundred eighty-nine million, four hundred forty thousand, six hundred forty".