21124197 has 12 divisors (see below), whose sum is σ = 31162560. Its totient is φ = 13782888.

The previous prime is 21124163. The next prime is 21124199. The reversal of 21124197 is 79142112.

It is not a de Polignac number, because 21124197 - 2⁷ = 21124069 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21124197.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124199) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24547 + ... + 25392.

It is an arithmetic number, because the mean of its divisors is an integer number (2596880).

Almost surely, 2^21124197 is an apocalyptic number.

It is an amenable number.

21124197 is a deficient number, since it is larger than the sum of its proper divisors (10038363).

21124197 is a wasteful number, since it uses less digits than its factorization.

21124197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49992 (or 49989 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 21124197 is about 4596.1067219985. The cubic root of 21124197 is about 276.4352379917.

It can be divided in two parts, 21124 and 197, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 21124197 in words is "twenty-one million, one hundred twenty-four thousand, one hundred ninety-seven".