16451781840 has 480 divisors, whose sum is σ = 62525998080. Its totient is φ = 3852610560.

The previous prime is 16451781779. The next prime is 16451781847. The reversal of 16451781840 is 4818715461.

16451781840 is a `hidden beast` number, since 16 + 4 + 517 + 81 + 8 + 40 = 666.

It is a super-2 number, since 2×16451781840² (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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16451781847) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 278843731 + ... + 278843789.

It is an arithmetic number, because the mean of its divisors is an integer number (130262496).

Almost surely, 2^16451781840 is an apocalyptic number.

16451781840 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 16451781840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31262999040).

16451781840 is an abundant number, since it is smaller than the sum of its proper divisors (46074216240).

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

16451781840 is a wasteful number, since it uses less digits than its factorization.

16451781840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 16451781840 in words is "sixteen billion, four hundred fifty-one million, seven hundred eighty-one thousand, eight hundred forty".