20861278245 has 30 divisors (see below), whose sum is σ = 37400984082. Its totient is φ = 11124464832.

The previous prime is 20861278241. The next prime is 20861278279. The reversal of 20861278245 is 54287216802.

20861278245 is a `hidden beast` number, since 2 + 0 + 8 + 612 + 7 + 8 + 24 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 11706807204 + 9154471041 = 108198^2 + 95679^2 .

It is not a de Polignac number, because 20861278245 - 2² = 20861278241 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20861278245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861278241) 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 29 ways as a sum of consecutive naturals, for example, 2903097 + ... + 2910273.

Almost surely, 2^20861278245 is an apocalyptic number.

It is an amenable number.

20861278245 is a deficient number, since it is larger than the sum of its proper divisors (16539705837).

20861278245 is an frugal number, since it uses more digits than its factorization.

20861278245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14371 (or 7185 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

Multiplying 20861278245 by its sum of digits (45), we get a square (938757521025 = 968895²).

20861278245 divided by its sum of digits (45) gives a square (463583961 = 21531²).

The spelling of 20861278245 in words is "twenty billion, eight hundred sixty-one million, two hundred seventy-eight thousand, two hundred forty-five".