21258867 has 16 divisors (see below), whose sum is σ = 32700672. Its totient is φ = 12033120.

The previous prime is 21258863. The next prime is 21258871. The reversal of 21258867 is 76885212.

It is an interprime number because it is at equal distance from previous prime (21258863) and next prime (21258871).

It is not a de Polignac number, because 21258867 - 2² = 21258863 is a prime.

It is a super-2 number, since 2×21258867² = 903878852247378, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21258863) 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 15 ways as a sum of consecutive naturals, for example, 2484 + ... + 6977.

It is an arithmetic number, because the mean of its divisors is an integer number (2043792).

Almost surely, 2^21258867 is an apocalyptic number.

21258867 is a deficient number, since it is larger than the sum of its proper divisors (11441805).

21258867 is a wasteful number, since it uses less digits than its factorization.

21258867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9578.

The product of its digits is 53760, while the sum is 39.

The square root of 21258867 is about 4610.7338895234. The cubic root of 21258867 is about 277.0214330881.

The spelling of 21258867 in words is "twenty-one million, two hundred fifty-eight thousand, eight hundred sixty-seven".