21198998 has 8 divisors (see below), whose sum is σ = 31867992. Its totient is φ = 10576336.

The previous prime is 21198997. The next prime is 21199019. The reversal of 21198998 is 89989112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21198997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10415 + ... + 12282.

It is an arithmetic number, because the mean of its divisors is an integer number (3983499).

Almost surely, 2^21198998 is an apocalyptic number.

21198998 is a deficient number, since it is larger than the sum of its proper divisors (10668994).

21198998 is a wasteful number, since it uses less digits than its factorization.

21198998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23166.

The product of its digits is 93312, while the sum is 47.

The square root of 21198998 is about 4604.2369617560. The cubic root of 21198998 is about 276.7611402981.

The spelling of 21198998 in words is "twenty-one million, one hundred ninety-eight thousand, nine hundred ninety-eight".