20261312643 has 16 divisors (see below), whose sum is σ = 31738000896. Its totient is φ = 11334999840.

The previous prime is 20261312633. The next prime is 20261312647. The reversal of 20261312643 is 34621316202.

It is not a de Polignac number, because 20261312643 - 2¹⁰ = 20261311619 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20261312643.

It is not an unprimeable number, because it can be changed into a prime (20261312647) 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 15 ways as a sum of consecutive naturals, for example, 23614155 + ... + 23615012.

It is an arithmetic number, because the mean of its divisors is an integer number (1983625056).

Almost surely, 2^20261312643 is an apocalyptic number.

20261312643 is a deficient number, since it is larger than the sum of its proper divisors (11476688253).

20261312643 is a wasteful number, since it uses less digits than its factorization.

20261312643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47229194.

The product of its (nonzero) digits is 10368, while the sum is 30.

Adding to 20261312643 its reverse (34621316202), we get a palindrome (54882628845).

The spelling of 20261312643 in words is "twenty billion, two hundred sixty-one million, three hundred twelve thousand, six hundred forty-three".