21919198 has 24 divisors (see below), whose sum is σ = 39666672. Its totient is φ = 8897472.

The previous prime is 21919189. The next prime is 21919213. The reversal of 21919198 is 89191912.

It is a self number, because there is not a number n which added to its sum of digits gives 21919198.

It is a congruent number.

It is an unprimeable number.

It is an upside-down number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2886 + ... + 7222.

It is an arithmetic number, because the mean of its divisors is an integer number (1652778).

Almost surely, 2^21919198 is an apocalyptic number.

21919198 is a deficient number, since it is larger than the sum of its proper divisors (17747474).

21919198 is a wasteful number, since it uses less digits than its factorization.

21919198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4384 (or 4365 counting only the distinct ones).

The product of its digits is 11664, while the sum is 40.

The square root of 21919198 is about 4681.7943141492. The cubic root of 21919198 is about 279.8604661913.

The spelling of 21919198 in words is "twenty-one million, nine hundred nineteen thousand, one hundred ninety-eight".