21230197 has 4 divisors (see below), whose sum is σ = 21250816. Its totient is φ = 21209580.

The previous prime is 21230179. The next prime is 21230203. The reversal of 21230197 is 79103212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21230197 - 2²³ = 12841589 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 (21230177) 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, 8679 + ... + 10852.

It is an arithmetic number, because the mean of its divisors is an integer number (5312704).

Almost surely, 2^21230197 is an apocalyptic number.

It is an amenable number.

21230197 is a deficient number, since it is larger than the sum of its proper divisors (20619).

21230197 is a wasteful number, since it uses less digits than its factorization.

21230197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20618.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21230197 is about 4607.6237910663. The cubic root of 21230197 is about 276.8968454280.

The spelling of 21230197 in words is "twenty-one million, two hundred thirty thousand, one hundred ninety-seven".