21129198 has 32 divisors (see below), whose sum is σ = 45515520. Its totient is φ = 6514560.

The previous prime is 21129191. The next prime is 21129209. The reversal of 21129198 is 89192112.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21129191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4263 + ... + 7773.

It is an arithmetic number, because the mean of its divisors is an integer number (1422360).

Almost surely, 2^21129198 is an apocalyptic number.

21129198 is an abundant number, since it is smaller than the sum of its proper divisors (24386322).

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

21129198 is a wasteful number, since it uses less digits than its factorization.

21129198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3592.

The product of its digits is 2592, while the sum is 33.

The square root of 21129198 is about 4596.6507372216. The cubic root of 21129198 is about 276.4570509478.

The spelling of 21129198 in words is "twenty-one million, one hundred twenty-nine thousand, one hundred ninety-eight".