20662261647 has 4 divisors (see below), whose sum is σ = 27549682200. Its totient is φ = 13774841096.

The previous prime is 20662261621. The next prime is 20662261687. The reversal of 20662261647 is 74616226602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20662261647 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20662261599 and 20662261608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20662261687) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3443710272 + ... + 3443710277.

It is an arithmetic number, because the mean of its divisors is an integer number (6887420550).

Almost surely, 2^20662261647 is an apocalyptic number.

20662261647 is a deficient number, since it is larger than the sum of its proper divisors (6887420553).

20662261647 is an equidigital number, since it uses as much as digits as its factorization.

20662261647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6887420552.

The product of its (nonzero) digits is 290304, while the sum is 42.

The spelling of 20662261647 in words is "twenty billion, six hundred sixty-two million, two hundred sixty-one thousand, six hundred forty-seven".