221296490778 has 144 divisors (see below), whose sum is σ = 527805677952. Its totient is φ = 61769241600.

The previous prime is 221296490771. The next prime is 221296490819. The reversal of 221296490778 is 877094692122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221296490771) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9850038 + ... + 9872478.

It is an arithmetic number, because the mean of its divisors is an integer number (3665317208).

Almost surely, 2^221296490778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221296490778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263902838976).

221296490778 is an abundant number, since it is smaller than the sum of its proper divisors (306509187174).

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

221296490778 is a wasteful number, since it uses less digits than its factorization.

221296490778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22549 (or 22521 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 57.

The spelling of 221296490778 in words is "two hundred twenty-one billion, two hundred ninety-six million, four hundred ninety thousand, seven hundred seventy-eight".