21197867 has 2 divisors, whose sum is σ = 21197868. Its totient is φ = 21197866.

The previous prime is 21197857. The next prime is 21197879. The reversal of 21197867 is 76879112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21197867 - 2⁴ = 21197851 is a prime.

It is not a weakly prime, because it can be changed into another prime (21197837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10598933 + 10598934.

It is an arithmetic number, because the mean of its divisors is an integer number (10598934).

Almost surely, 2^21197867 is an apocalyptic number.

21197867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21197867 is an equidigital number, since it uses as much as digits as its factorization.

21197867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 41.

The square root of 21197867 is about 4604.1141384636. The cubic root of 21197867 is about 276.7562183293.

The spelling of 21197867 in words is "twenty-one million, one hundred ninety-seven thousand, eight hundred sixty-seven".