21029028856 has 32 divisors (see below), whose sum is σ = 43019729280. Its totient is φ = 9557359200.

The previous prime is 21029028841. The next prime is 21029028859. The reversal of 21029028856 is 65882092012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21029028859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1004011 + ... + 1024741.

It is an arithmetic number, because the mean of its divisors is an integer number (1344366540).

Almost surely, 2^21029028856 is an apocalyptic number.

It is an amenable number.

21029028856 is an abundant number, since it is smaller than the sum of its proper divisors (21990700424).

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

21029028856 is a wasteful number, since it uses less digits than its factorization.

21029028856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32275 (or 32271 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 43.

The spelling of 21029028856 in words is "twenty-one billion, twenty-nine million, twenty-eight thousand, eight hundred fifty-six".