21799198 has 16 divisors (see below), whose sum is σ = 33233760. Its totient is φ = 10722816.

The previous prime is 21799189. The next prime is 21799199. The reversal of 21799198 is 89199712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21799199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60543 + ... + 60901.

It is an arithmetic number, because the mean of its divisors is an integer number (2077110).

Almost surely, 2^21799198 is an apocalyptic number.

21799198 is a deficient number, since it is larger than the sum of its proper divisors (11434562).

21799198 is a wasteful number, since it uses less digits than its factorization.

21799198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771.

The product of its digits is 81648, while the sum is 46.

The square root of 21799198 is about 4668.9611264177. The cubic root of 21799198 is about 279.3488183870.

It can be divided in two parts, 217991 and 98, that added together give a square (218089 = 467²).

The spelling of 21799198 in words is "twenty-one million, seven hundred ninety-nine thousand, one hundred ninety-eight".