221894428428 has 96 divisors (see below), whose sum is σ = 601171415040. Its totient is φ = 71578760400.

The previous prime is 221894428279. The next prime is 221894428501. The reversal of 221894428428 is 824824498122.

It is a happy number.

221894428428 is a `hidden beast` number, since 2 + 21 + 89 + 442 + 84 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 137928 + ... + 680303.

It is an arithmetic number, because the mean of its divisors is an integer number (6262202240).

Almost surely, 2^221894428428 is an apocalyptic number.

It is an amenable number.

221894428428 is an abundant number, since it is smaller than the sum of its proper divisors (379276986612).

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

221894428428 is an equidigital number, since it uses as much as digits as its factorization.

221894428428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 818287 (or 818267 counting only the distinct ones).

The product of its digits is 4718592, while the sum is 54.

It can be divided in two parts, 221 and 894428428, that added together give a square (894428649 = 29907²).

The spelling of 221894428428 in words is "two hundred twenty-one billion, eight hundred ninety-four million, four hundred twenty-eight thousand, four hundred twenty-eight".