21258308 has 12 divisors (see below), whose sum is σ = 37248960. Its totient is φ = 10615752.

The previous prime is 21258301. The next prime is 21258329. The reversal of 21258308 is 80385212.

It is not an unprimeable number, because it can be changed into a prime (21258301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 785 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (3104080).

Almost surely, 2^21258308 is an apocalyptic number.

It is an amenable number.

21258308 is a deficient number, since it is larger than the sum of its proper divisors (15990652).

21258308 is a wasteful number, since it uses less digits than its factorization.

21258308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6706 (or 6704 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 21258308 is about 4610.6732697080. The cubic root of 21258308 is about 277.0190049822.

The spelling of 21258308 in words is "twenty-one million, two hundred fifty-eight thousand, three hundred eight".