21042049776 has 320 divisors, whose sum is σ = 64975841280. Its totient is φ = 5798200320.

The previous prime is 21042049747. The next prime is 21042049783. The reversal of 21042049776 is 67794024012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30807931 + ... + 30808613.

It is an arithmetic number, because the mean of its divisors is an integer number (203049504).

Almost surely, 2^21042049776 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 21042049776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32487920640).

21042049776 is an abundant number, since it is smaller than the sum of its proper divisors (43933791504).

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

21042049776 is a wasteful number, since it uses less digits than its factorization.

21042049776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844 (or 838 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 42.

The spelling of 21042049776 in words is "twenty-one billion, forty-two million, forty-nine thousand, seven hundred seventy-six".