221955191378 has 18 divisors (see below), whose sum is σ = 335625639447. Its totient is φ = 110087131180.

The previous prime is 221955191377. The next prime is 221955191429. The reversal of 221955191378 is 873191559122.

It can be written as a sum of positive squares in only one way, i.e., 110977595689 + 110977595689 = 333133^2 + 333133^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=333133.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221955191371) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 87279575 + ... + 87282117.

Almost surely, 2^221955191378 is an apocalyptic number.

221955191378 is a deficient number, since it is larger than the sum of its proper divisors (113670448069).

221955191378 is an frugal number, since it uses more digits than its factorization.

221955191378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5350 (or 2676 counting only the distinct ones).

The product of its digits is 1360800, while the sum is 53.

The spelling of 221955191378 in words is "two hundred twenty-one billion, nine hundred fifty-five million, one hundred ninety-one thousand, three hundred seventy-eight".