1605226561 has 4 divisors (see below), whose sum is σ = 1615451092. Its totient is φ = 1595002032.

The previous prime is 1605226559. The next prime is 1605226573. The reversal of 1605226561 is 1656225061.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1074200625 + 531025936 = 32775^2 + 23044^2 .

It is a cyclic number.

It is not a de Polignac number, because 1605226561 - 2¹ = 1605226559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1605226501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5112030 + ... + 5112343.

It is an arithmetic number, because the mean of its divisors is an integer number (403862773).

Almost surely, 2^1605226561 is an apocalyptic number.

It is an amenable number.

1605226561 is a deficient number, since it is larger than the sum of its proper divisors (10224531).

1605226561 is a wasteful number, since it uses less digits than its factorization.

1605226561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10224530.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 1605226561 is about 40065.2787460664. The cubic root of 1605226561 is about 1170.8792574966.

The spelling of 1605226561 in words is "one billion, six hundred five million, two hundred twenty-six thousand, five hundred sixty-one".