21198164 has 12 divisors (see below), whose sum is σ = 39950484. Its totient is φ = 9783744.

The previous prime is 21198161. The next prime is 21198179. The reversal of 21198164 is 46189112.

It can be written as a sum of positive squares in 2 ways, for example, as 7075600 + 14122564 = 2660^2 + 3758^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21198164.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21198161) 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, 203777 + ... + 203880.

It is an arithmetic number, because the mean of its divisors is an integer number (3329207).

Almost surely, 2^21198164 is an apocalyptic number.

It is an amenable number.

21198164 is a deficient number, since it is larger than the sum of its proper divisors (18752320).

21198164 is a wasteful number, since it uses less digits than its factorization.

21198164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407674 (or 407672 counting only the distinct ones).

The product of its digits is 3456, while the sum is 32.

The square root of 21198164 is about 4604.1463921122. The cubic root of 21198164 is about 276.7575108526.

The spelling of 21198164 in words is "twenty-one million, one hundred ninety-eight thousand, one hundred sixty-four".