21002763888 has 80 divisors (see below), whose sum is σ = 60346137600. Its totient is φ = 6993904320.

The previous prime is 21002763877. The next prime is 21002763889. The reversal of 21002763888 is 88836720012.

21002763888 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 2 + 7 + 638 + 8 + 8 = 666.

It is a super-2 number, since 2×21002763888² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002763889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 416353 + ... + 464063.

It is an arithmetic number, because the mean of its divisors is an integer number (754326720).

Almost surely, 2^21002763888 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 21002763888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30173068800).

21002763888 is an abundant number, since it is smaller than the sum of its proper divisors (39343373712).

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

21002763888 is a wasteful number, since it uses less digits than its factorization.

21002763888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48747 (or 48735 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 21002763888 in words is "twenty-one billion, two million, seven hundred sixty-three thousand, eight hundred eighty-eight".