21342197 has 4 divisors (see below), whose sum is σ = 21531180. Its totient is φ = 21153216.

The previous prime is 21342193. The next prime is 21342203. The reversal of 21342197 is 79124312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8994001 + 12348196 = 2999^2 + 3514^2 .

It is a cyclic number.

It is not a de Polignac number, because 21342197 - 2² = 21342193 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21342193) 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, 94322 + ... + 94547.

It is an arithmetic number, because the mean of its divisors is an integer number (5382795).

Almost surely, 2^21342197 is an apocalyptic number.

It is an amenable number.

21342197 is a deficient number, since it is larger than the sum of its proper divisors (188983).

21342197 is a wasteful number, since it uses less digits than its factorization.

21342197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188982.

The product of its digits is 3024, while the sum is 29.

The square root of 21342197 is about 4619.7615739343. The cubic root of 21342197 is about 277.3829151919.

The spelling of 21342197 in words is "twenty-one million, three hundred forty-two thousand, one hundred ninety-seven".