21105198 has 20 divisors (see below), whose sum is σ = 47291640. Its totient is φ = 7035012.

The previous prime is 21105197. The next prime is 21105199. The reversal of 21105198 is 89150112.

It is an interprime number because it is at equal distance from previous prime (21105197) and next prime (21105199).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105197) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 64978 + ... + 65301.

It is an arithmetic number, because the mean of its divisors is an integer number (2364582).

Almost surely, 2^21105198 is an apocalyptic number.

21105198 is an abundant number, since it is smaller than the sum of its proper divisors (26186442).

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

21105198 is a wasteful number, since it uses less digits than its factorization.

21105198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130293 (or 130284 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 21105198 is about 4594.0393990474. The cubic root of 21105198 is about 276.3523382975.

The spelling of 21105198 in words is "twenty-one million, one hundred five thousand, one hundred ninety-eight".