21320238 has 16 divisors (see below), whose sum is σ = 42685776. Its totient is φ = 7099200.

The previous prime is 21320213. The next prime is 21320239. The reversal of 21320238 is 83202312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320239) by changing a digit.

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, 9820 + ... + 11792.

It is an arithmetic number, because the mean of its divisors is an integer number (2667861).

Almost surely, 2^21320238 is an apocalyptic number.

21320238 is an abundant number, since it is smaller than the sum of its proper divisors (21365538).

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

21320238 is a wasteful number, since it uses less digits than its factorization.

21320238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3779.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21320238 is about 4617.3843244850. The cubic root of 21320238 is about 277.2877493934.

The spelling of 21320238 in words is "twenty-one million, three hundred twenty thousand, two hundred thirty-eight".