16991078400 has 720 divisors, whose sum is σ = 66909662820. Its totient is φ = 4246732800.

The previous prime is 16991078387. The next prime is 16991078441. The reversal of 16991078400 is 487019961.

It is a happy number.

16991078400 is a `hidden beast` number, since 169 + 9 + 10 + 78 + 400 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 10809345024 + 6181733376 = 103968^2 + 78624^2 .

It is a tau number, because it is divible by the number of its divisors (720).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 70502280 + ... + 70502520.

Almost surely, 2^16991078400 is an apocalyptic number.

16991078400 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 16991078400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33454831410).

16991078400 is an abundant number, since it is smaller than the sum of its proper divisors (49918584420).

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

16991078400 is a wasteful number, since it uses less digits than its factorization.

16991078400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The spelling of 16991078400 in words is "sixteen billion, nine hundred ninety-one million, seventy-eight thousand, four hundred".