21258716 has 24 divisors (see below), whose sum is σ = 38997504. Its totient is φ = 10120880.

The previous prime is 21258691. The next prime is 21258733. The reversal of 21258716 is 61785212.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 28241 + ... + 28983.

It is an arithmetic number, because the mean of its divisors is an integer number (1624896).

Almost surely, 2^21258716 is an apocalyptic number.

It is an amenable number.

21258716 is a deficient number, since it is larger than the sum of its proper divisors (17738788).

21258716 is a wasteful number, since it uses less digits than its factorization.

21258716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081 (or 1079 counting only the distinct ones).

The product of its digits is 6720, while the sum is 32.

The square root of 21258716 is about 4610.7175146608. The cubic root of 21258716 is about 277.0207771996.

The spelling of 21258716 in words is "twenty-one million, two hundred fifty-eight thousand, seven hundred sixteen".