21351202768 has 120 divisors (see below), whose sum is σ = 51142902984. Its totient is φ = 8580096000.

The previous prime is 21351202711. The next prime is 21351202813. The reversal of 21351202768 is 86720215312.

It can be written as a sum of positive squares in 4 ways, for example, as 11476408384 + 9874794384 = 107128^2 + 99372^2 .

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 3742318 + ... + 3748018.

Almost surely, 2^21351202768 is an apocalyptic number.

21351202768 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21351202768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25571451492).

21351202768 is an abundant number, since it is smaller than the sum of its proper divisors (29791700216).

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

21351202768 is a wasteful number, since it uses less digits than its factorization.

21351202768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6021 (or 6008 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The spelling of 21351202768 in words is "twenty-one billion, three hundred fifty-one million, two hundred two thousand, seven hundred sixty-eight".