20965881616 has 45 divisors (see below), whose sum is σ = 41463005269. Its totient is φ = 10270090688.

The previous prime is 20965881593. The next prime is 20965881617. The reversal of 20965881616 is 61618856902.

The square root of 20965881616 is 144796.

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

It can be written as a sum of positive squares in only one way, i.e., 15114243600 + 5851638016 = 122940^2 + 76496^2 .

It is a super-2 number, since 2×20965881616² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20965881617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 30696411 + ... + 30697093.

Almost surely, 2^20965881616 is an apocalyptic number.

20965881616 is the 144796-th square number.

It is an amenable number.

20965881616 is a deficient number, since it is larger than the sum of its proper divisors (20497123653).

20965881616 is an frugal number, since it uses more digits than its factorization.

20965881616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1480 (or 738 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 52.

The spelling of 20965881616 in words is "twenty billion, nine hundred sixty-five million, eight hundred eighty-one thousand, six hundred sixteen".