21002965776 has 135 divisors (see below), whose sum is σ = 63716997279. Its totient is φ = 6455494656.

The previous prime is 21002965733. The next prime is 21002965783. The reversal of 21002965776 is 67756920012.

The square root of 21002965776 is 144924.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 15560067600 + 5442898176 = 124740^2 + 73776^2 .

It is a super-2 number, since 2×21002965776² (a number of 21 digits) contains 22 as substring.

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 26 ways as a sum of consecutive naturals, for example, 22607680 + ... + 22608608.

Almost surely, 2^21002965776 is an apocalyptic number.

21002965776 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21002965776 is the 144924-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002965776

21002965776 is an abundant number, since it is smaller than the sum of its proper divisors (42714031503).

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

21002965776 is an equidigital number, since it uses as much as digits as its factorization.

21002965776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1898 (or 947 counting only the distinct ones).

The product of its (nonzero) digits is 317520, while the sum is 45.

The spelling of 21002965776 in words is "twenty-one billion, two million, nine hundred sixty-five thousand, seven hundred seventy-six".