21198258 has 12 divisors (see below), whose sum is σ = 45929598. Its totient is φ = 7066080.

The previous prime is 21198253. The next prime is 21198263. The reversal of 21198258 is 85289112.

It is an interprime number because it is at equal distance from previous prime (21198253) and next prime (21198263).

It can be written as a sum of positive squares in only one way, i.e., 17614809 + 3583449 = 4197^2 + 1893^2 .

It is a super-2 number, since 2×21198258² = 898732284469128, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21198253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 588823 + ... + 588858.

Almost surely, 2^21198258 is an apocalyptic number.

21198258 is an abundant number, since it is smaller than the sum of its proper divisors (24731340).

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

21198258 is a wasteful number, since it uses less digits than its factorization.

21198258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1177689 (or 1177686 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21198258 is about 4604.1566002907. The cubic root of 21198258 is about 276.7579199316.

The spelling of 21198258 in words is "twenty-one million, one hundred ninety-eight thousand, two hundred fifty-eight".