21258771 has 4 divisors (see below), whose sum is σ = 28345032. Its totient is φ = 14172512.

The previous prime is 21258767. The next prime is 21258779. The reversal of 21258771 is 17785212.

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 21258771 - 2² = 21258767 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21258779) 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, 3543126 + ... + 3543131.

It is an arithmetic number, because the mean of its divisors is an integer number (7086258).

Almost surely, 2^21258771 is an apocalyptic number.

21258771 is a deficient number, since it is larger than the sum of its proper divisors (7086261).

21258771 is an equidigital number, since it uses as much as digits as its factorization.

21258771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7086260.

The product of its digits is 7840, while the sum is 33.

The square root of 21258771 is about 4610.7234790215. The cubic root of 21258771 is about 277.0210160998.

The spelling of 21258771 in words is "twenty-one million, two hundred fifty-eight thousand, seven hundred seventy-one".