20645561547 has 48 divisors (see below), whose sum is σ = 32656478400. Its totient is φ = 12491861760.

The previous prime is 20645561537. The next prime is 20645561609. The reversal of 20645561547 is 74516554602.

20645561547 is a `hidden beast` number, since 2 + 0 + 6 + 45 + 5 + 61 + 547 = 666.

It is not a de Polignac number, because 20645561547 - 2¹¹ = 20645559499 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20645561527) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3228229 + ... + 3234617.

It is an arithmetic number, because the mean of its divisors is an integer number (680343300).

Almost surely, 2^20645561547 is an apocalyptic number.

20645561547 is a deficient number, since it is larger than the sum of its proper divisors (12010916853).

20645561547 is a wasteful number, since it uses less digits than its factorization.

20645561547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6868 (or 6865 counting only the distinct ones).

The product of its (nonzero) digits is 1008000, while the sum is 45.

The spelling of 20645561547 in words is "twenty billion, six hundred forty-five million, five hundred sixty-one thousand, five hundred forty-seven".