21931198 has 16 divisors (see below), whose sum is σ = 34107264. Its totient is φ = 10565280.

The previous prime is 21931157. The next prime is 21931199. The reversal of 21931198 is 89113912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21931199) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16536 + ... + 17812.

It is an arithmetic number, because the mean of its divisors is an integer number (2131704).

Almost surely, 2^21931198 is an apocalyptic number.

21931198 is a deficient number, since it is larger than the sum of its proper divisors (12176066).

21931198 is a wasteful number, since it uses less digits than its factorization.

21931198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1587.

The product of its digits is 3888, while the sum is 34.

The square root of 21931198 is about 4683.0756987262. The cubic root of 21931198 is about 279.9115281709.

The spelling of 21931198 in words is "twenty-one million, nine hundred thirty-one thousand, one hundred ninety-eight".