21698184078 has 48 divisors (see below), whose sum is σ = 47468768256. Its totient is φ = 7162907280.

The previous prime is 21698184049. The next prime is 21698184103. The reversal of 21698184078 is 87048189612.

21698184078 is a `hidden beast` number, since 216 + 9 + 8 + 18 + 407 + 8 = 666.

It is a super-2 number, since 2×21698184078² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 766525 + ... + 794327.

It is an arithmetic number, because the mean of its divisors is an integer number (988932672).

Almost surely, 2^21698184078 is an apocalyptic number.

21698184078 is an abundant number, since it is smaller than the sum of its proper divisors (25770584178).

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

21698184078 is a wasteful number, since it uses less digits than its factorization.

21698184078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28229 (or 28226 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 21698184078 in words is "twenty-one billion, six hundred ninety-eight million, one hundred eighty-four thousand, seventy-eight".