16821814464 has 756 divisors, whose sum is σ = 64251742464. Its totient is φ = 4169926656.

The previous prime is 16821814463. The next prime is 16821814489. The reversal of 16821814464 is 46441812861.

16821814464 is a `hidden beast` number, since 1 + 6 + 8 + 2 + 181 + 4 + 464 = 666.

It is a super-2 number, since 2×16821814464² (a number of 21 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16821814463) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 132455169 + ... + 132455295.

Almost surely, 2^16821814464 is an apocalyptic number.

16821814464 is a gapful number since it is divisible by the number (14) 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 16821814464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32125871232).

16821814464 is an abundant number, since it is smaller than the sum of its proper divisors (47429928000).

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

16821814464 is a wasteful number, since it uses less digits than its factorization.

16821814464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210 (or 171 counting only the distinct ones).

The product of its digits is 294912, while the sum is 45.

The spelling of 16821814464 in words is "sixteen billion, eight hundred twenty-one million, eight hundred fourteen thousand, four hundred sixty-four".