20643325216 has 24 divisors (see below), whose sum is σ = 43032226860. Its totient is φ = 9714505728.

The previous prime is 20643325207. The next prime is 20643325231. The reversal of 20643325216 is 61252334602.

It can be written as a sum of positive squares in 2 ways, for example, as 20569296400 + 74028816 = 143420^2 + 8604^2 .

It is a super-2 number, since 2×20643325216² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18973101 + ... + 18974188.

Almost surely, 2^20643325216 is an apocalyptic number.

It is an amenable number.

20643325216 is an abundant number, since it is smaller than the sum of its proper divisors (22388901644).

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

20643325216 is a wasteful number, since it uses less digits than its factorization.

20643325216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37947316 (or 37947308 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 34.

Adding to 20643325216 its reverse (61252334602), we get a palindrome (81895659818).

The spelling of 20643325216 in words is "twenty billion, six hundred forty-three million, three hundred twenty-five thousand, two hundred sixteen".