21142867 has 2 divisors, whose sum is σ = 21142868. Its totient is φ = 21142866.

The previous prime is 21142859. The next prime is 21142871. The reversal of 21142867 is 76824112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21142867 - 2³ = 21142859 is a prime.

It is not a weakly prime, because it can be changed into another prime (21142817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571433 + 10571434.

It is an arithmetic number, because the mean of its divisors is an integer number (10571434).

Almost surely, 2^21142867 is an apocalyptic number.

21142867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142867 is an equidigital number, since it uses as much as digits as its factorization.

21142867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 31.

The square root of 21142867 is about 4598.1373402716. The cubic root of 21142867 is about 276.5166537280.

Adding to 21142867 its reverse (76824112), we get a palindrome (97966979).

The spelling of 21142867 in words is "twenty-one million, one hundred forty-two thousand, eight hundred sixty-seven".