21214197 has 16 divisors (see below), whose sum is σ = 31514880. Its totient is φ = 14103936.

The previous prime is 21214187. The next prime is 21214229. The reversal of 21214197 is 79141212.

It is not a de Polignac number, because 21214197 - 2⁶ = 21214133 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21214197.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21214117) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11653 + ... + 13349.

It is an arithmetic number, because the mean of its divisors is an integer number (1969680).

Almost surely, 2^21214197 is an apocalyptic number.

21214197 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21214197 is a deficient number, since it is larger than the sum of its proper divisors (10300683).

21214197 is a wasteful number, since it uses less digits than its factorization.

21214197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2169 (or 2163 counting only the distinct ones).

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

The square root of 21214197 is about 4605.8872109508. The cubic root of 21214197 is about 276.8272674434.

The spelling of 21214197 in words is "twenty-one million, two hundred fourteen thousand, one hundred ninety-seven".