21849725178 has 12 divisors (see below), whose sum is σ = 47341071258. Its totient is φ = 7283241720.

The previous prime is 21849725137. The next prime is 21849725179. The reversal of 21849725178 is 87152794812.

21849725178 is a `hidden beast` number, since 2 + 18 + 49 + 72 + 517 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20823355809 + 1026369369 = 144303^2 + 32037^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21849725179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 606936793 + ... + 606936828.

Almost surely, 2^21849725178 is an apocalyptic number.

21849725178 is an abundant number, since it is smaller than the sum of its proper divisors (25491346080).

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

21849725178 is a wasteful number, since it uses less digits than its factorization.

21849725178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1213873629 (or 1213873626 counting only the distinct ones).

The product of its digits is 2257920, while the sum is 54.

The spelling of 21849725178 in words is "twenty-one billion, eight hundred forty-nine million, seven hundred twenty-five thousand, one hundred seventy-eight".