21021020238 has 8 divisors (see below), whose sum is σ = 42042040488. Its totient is φ = 7007006744.

The previous prime is 21021020161. The next prime is 21021020239. The reversal of 21021020238 is 83202012012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21021020238 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021020239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751751681 + ... + 1751751692.

It is an arithmetic number, because the mean of its divisors is an integer number (5255255061).

Almost surely, 2^21021020238 is an apocalyptic number.

21021020238 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21021020238 is a wasteful number, since it uses less digits than its factorization.

21021020238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3503503378.

The product of its (nonzero) digits is 384, while the sum is 21.

The spelling of 21021020238 in words is "twenty-one billion, twenty-one million, twenty thousand, two hundred thirty-eight".