21420234198 has 48 divisors (see below), whose sum is σ = 50639427072. Its totient is φ = 6489726000.

The previous prime is 21420234181. The next prime is 21420234211. The reversal of 21420234198 is 89143202412.

21420234198 is a `hidden beast` number, since 21 + 4 + 202 + 341 + 98 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1861603 + ... + 1873073.

It is an arithmetic number, because the mean of its divisors is an integer number (1054988064).

Almost surely, 2^21420234198 is an apocalyptic number.

21420234198 is an abundant number, since it is smaller than the sum of its proper divisors (29219192874).

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

21420234198 is a wasteful number, since it uses less digits than its factorization.

21420234198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20921 (or 20918 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 21420234198 in words is "twenty-one billion, four hundred twenty million, two hundred thirty-four thousand, one hundred ninety-eight".