221813790978 has 32 divisors (see below), whose sum is σ = 478789198272. Its totient is φ = 68102337600.

The previous prime is 221813790973. The next prime is 221813790997. The reversal of 221813790978 is 879097318122.

221813790978 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (221813790973) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3048388 + ... + 3120303.

It is an arithmetic number, because the mean of its divisors is an integer number (14962162446).

Almost surely, 2^221813790978 is an apocalyptic number.

221813790978 is an abundant number, since it is smaller than the sum of its proper divisors (256975407294).

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

221813790978 is a wasteful number, since it uses less digits than its factorization.

221813790978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6169170.

The product of its (nonzero) digits is 3048192, while the sum is 57.

The spelling of 221813790978 in words is "two hundred twenty-one billion, eight hundred thirteen million, seven hundred ninety thousand, nine hundred seventy-eight".