21258967 has 4 divisors (see below), whose sum is σ = 22377880. Its totient is φ = 20140056.

The previous prime is 21258917. The next prime is 21258973. The reversal of 21258967 is 76985212.

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 21258967 - 2¹⁵ = 21226199 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21258907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 559428 + ... + 559465.

It is an arithmetic number, because the mean of its divisors is an integer number (5594470).

Almost surely, 2^21258967 is an apocalyptic number.

21258967 is a deficient number, since it is larger than the sum of its proper divisors (1118913).

21258967 is a wasteful number, since it uses less digits than its factorization.

21258967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118912.

The product of its digits is 60480, while the sum is 40.

The square root of 21258967 is about 4610.7447337713. The cubic root of 21258967 is about 277.0218674496.

The spelling of 21258967 in words is "twenty-one million, two hundred fifty-eight thousand, nine hundred sixty-seven".