1604262221 has 4 divisors (see below), whose sum is σ = 1604351100. Its totient is φ = 1604173344.

The previous prime is 1604262199. The next prime is 1604262269. The reversal of 1604262221 is 1222624061.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1222624061 = 89 ⋅13737349.

It can be written as a sum of positive squares in 2 ways, for example, as 1278062500 + 326199721 = 35750^2 + 18061^2 .

It is a cyclic number.

It is not a de Polignac number, because 1604262221 - 2⁶ = 1604262157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1604261221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6656 + ... + 57033.

It is an arithmetic number, because the mean of its divisors is an integer number (401087775).

Almost surely, 2^1604262221 is an apocalyptic number.

It is an amenable number.

1604262221 is a deficient number, since it is larger than the sum of its proper divisors (88879).

1604262221 is an equidigital number, since it uses as much as digits as its factorization.

1604262221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88878.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 1604262221 is about 40053.2423281811. The cubic root of 1604262221 is about 1170.6447419224.

Adding to 1604262221 its reverse (1222624061), we get a palindrome (2826886282).

The spelling of 1604262221 in words is "one billion, six hundred four million, two hundred sixty-two thousand, two hundred twenty-one".