221664794450 has 54 divisors (see below), whose sum is σ = 453260310447. Its totient is φ = 80592063200.

The previous prime is 221664794431. The next prime is 221664794501. The reversal of 221664794450 is 54497466122.

It can be written as a sum of positive squares in 5 ways, for example, as 3817633369 + 217847161081 = 61787^2 + 466741^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=332915.

It is a Harshad number since it is a multiple of its sum of digits (50).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 36617624 + ... + 36623676.

Almost surely, 2^221664794450 is an apocalyptic number.

221664794450 is an abundant number, since it is smaller than the sum of its proper divisors (231595515997).

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

221664794450 is an frugal number, since it uses more digits than its factorization.

221664794450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12140 (or 6071 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 50.

Multiplying 221664794450 by its sum of digits (50), we get a square (11083239722500 = 3329150²).

221664794450 divided by its sum of digits (50) gives a square (4433295889 = 66583²).

The spelling of 221664794450 in words is "two hundred twenty-one billion, six hundred sixty-four million, seven hundred ninety-four thousand, four hundred fifty".