16581878838 has 48 divisors (see below), whose sum is σ = 41067237120. Its totient is φ = 4736832048.

The previous prime is 16581878837. The next prime is 16581878849. The reversal of 16581878838 is 83887818561.

16581878838 is a `hidden beast` number, since 16 + 581 + 8 + 7 + 8 + 8 + 38 = 666.

It is a super-2 number, since 2×16581878838² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16581878837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1142793 + ... + 1157211.

It is an arithmetic number, because the mean of its divisors is an integer number (855567440).

Almost surely, 2^16581878838 is an apocalyptic number.

16581878838 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

16581878838 is an abundant number, since it is smaller than the sum of its proper divisors (24485358282).

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

16581878838 is a wasteful number, since it uses less digits than its factorization.

16581878838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23561 (or 23558 counting only the distinct ones).

The product of its digits is 20643840, while the sum is 63.

The spelling of 16581878838 in words is "sixteen billion, five hundred eighty-one million, eight hundred seventy-eight thousand, eight hundred thirty-eight".