21010867 has 4 divisors (see below), whose sum is σ = 21214960. Its totient is φ = 20806776.

The previous prime is 21010859. The next prime is 21010883. The reversal of 21010867 is 76801012.

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

It is a cyclic number.

It is not a de Polignac number, because 21010867 - 2³ = 21010859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21010567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101892 + ... + 102097.

It is an arithmetic number, because the mean of its divisors is an integer number (5303740).

Almost surely, 2^21010867 is an apocalyptic number.

21010867 is a deficient number, since it is larger than the sum of its proper divisors (204093).

21010867 is a wasteful number, since it uses less digits than its factorization.

21010867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204092.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21010867 is about 4583.7612285109. The cubic root of 21010867 is about 275.9399986841.

Adding to 21010867 its reverse (76801012), we get a palindrome (97811879).

The spelling of 21010867 in words is "twenty-one million, ten thousand, eight hundred sixty-seven".