21211197 has 16 divisors (see below), whose sum is σ = 32481792. Its totient is φ = 12060720.

The previous prime is 21211181. The next prime is 21211217. The reversal of 21211197 is 79111212.

It is not a de Polignac number, because 21211197 - 2⁴ = 21211181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211997) 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, 2038 + ... + 6824.

It is an arithmetic number, because the mean of its divisors is an integer number (2030112).

Almost surely, 2^21211197 is an apocalyptic number.

It is an amenable number.

21211197 is a deficient number, since it is larger than the sum of its proper divisors (11270595).

21211197 is a wasteful number, since it uses less digits than its factorization.

21211197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5008.

The product of its digits is 252, while the sum is 24.

The square root of 21211197 is about 4605.5615292817. The cubic root of 21211197 is about 276.8142176769.

The spelling of 21211197 in words is "twenty-one million, two hundred eleven thousand, one hundred ninety-seven".