21305638198 has 32 divisors (see below), whose sum is σ = 34779435264. Its totient is φ = 9729980832.

The previous prime is 21305638187. The next prime is 21305638261. The reversal of 21305638198 is 89183650312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2630511 + ... + 2638597.

It is an arithmetic number, because the mean of its divisors is an integer number (1086857352).

Almost surely, 2^21305638198 is an apocalyptic number.

21305638198 is a deficient number, since it is larger than the sum of its proper divisors (13473797066).

21305638198 is a wasteful number, since it uses less digits than its factorization.

21305638198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9156.

The product of its (nonzero) digits is 311040, while the sum is 46.

The spelling of 21305638198 in words is "twenty-one billion, three hundred five million, six hundred thirty-eight thousand, one hundred ninety-eight".