21308238 has 48 divisors (see below), whose sum is σ = 55089360. Its totient is φ = 6087312.

The previous prime is 21308219. The next prime is 21308299. The reversal of 21308238 is 83280312.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 23 ways as a sum of consecutive naturals, for example, 1381 + ... + 6672.

It is an arithmetic number, because the mean of its divisors is an integer number (1147695).

Almost surely, 2^21308238 is an apocalyptic number.

21308238 is an abundant number, since it is smaller than the sum of its proper divisors (33781122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21308238 is a wasteful number, since it uses less digits than its factorization.

21308238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8078 (or 8065 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21308238 is about 4616.0847045954. The cubic root of 21308238 is about 277.2357162427.

The spelling of 21308238 in words is "twenty-one million, three hundred eight thousand, two hundred thirty-eight".