21028028308 has 36 divisors (see below), whose sum is σ = 44276575840. Its totient is φ = 8536337712.

The previous prime is 21028028291. The next prime is 21028028339. The reversal of 21028028308 is 80382082012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3341541 + ... + 3347827.

Almost surely, 2^21028028308 is an apocalyptic number.

21028028308 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21028028308 is an abundant number, since it is smaller than the sum of its proper divisors (23248547532).

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

21028028308 is an frugal number, since it uses more digits than its factorization.

21028028308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12604 (or 6315 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 34.

The spelling of 21028028308 in words is "twenty-one billion, twenty-eight million, twenty-eight thousand, three hundred eight".