21860864778 has 32 divisors (see below), whose sum is σ = 43915700160. Its totient is φ = 7254696960.

The previous prime is 21860864777. The next prime is 21860864803. The reversal of 21860864778 is 87746806812.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21860864777) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1303768 + ... + 1320428.

It is an arithmetic number, because the mean of its divisors is an integer number (1372365630).

Almost surely, 2^21860864778 is an apocalyptic number.

21860864778 is an abundant number, since it is smaller than the sum of its proper divisors (22054835382).

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

21860864778 is a wasteful number, since it uses less digits than its factorization.

21860864778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17622.

The product of its (nonzero) digits is 7225344, while the sum is 57.

The spelling of 21860864778 in words is "twenty-one billion, eight hundred sixty million, eight hundred sixty-four thousand, seven hundred seventy-eight".