21020030208 has 108 divisors (see below), whose sum is σ = 61336679040. Its totient is φ = 6922195968.

The previous prime is 21020030203. The next prime is 21020030209. The reversal of 21020030208 is 80203002012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020030203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136273 + ... + 246191.

Almost surely, 2^21020030208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020030208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30668339520).

21020030208 is an abundant number, since it is smaller than the sum of its proper divisors (40316648832).

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

21020030208 is a wasteful number, since it uses less digits than its factorization.

21020030208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110024 (or 110007 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The spelling of 21020030208 in words is "twenty-one billion, twenty million, thirty thousand, two hundred eight".