221051707878 has 16 divisors (see below), whose sum is σ = 442221891696. Its totient is φ = 73664156640.

The previous prime is 221051707817. The next prime is 221051707879. The reversal of 221051707878 is 878707150122.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221051707879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4912233 + ... + 4957028.

It is an arithmetic number, because the mean of its divisors is an integer number (27638868231).

Almost surely, 2^221051707878 is an apocalyptic number.

221051707878 is an abundant number, since it is smaller than the sum of its proper divisors (221170183818).

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

221051707878 is a wasteful number, since it uses less digits than its factorization.

221051707878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9872999.

The product of its (nonzero) digits is 439040, while the sum is 48.

The spelling of 221051707878 in words is "two hundred twenty-one billion, fifty-one million, seven hundred seven thousand, eight hundred seventy-eight".