1605406561 has 8 divisors (see below), whose sum is σ = 1759003200. Its totient is φ = 1453085040.

The previous prime is 1605406559. The next prime is 1605406597. The reversal of 1605406561 is 1656045061.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1605406561 - 2¹ = 1605406559 is a prime.

It is a super-2 number, since 2×1605406561² = 5154660452203693442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1605406511) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 316141 + ... + 321178.

It is an arithmetic number, because the mean of its divisors is an integer number (219875400).

Almost surely, 2^1605406561 is an apocalyptic number.

1605406561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1605406561 is a deficient number, since it is larger than the sum of its proper divisors (153596639).

1605406561 is a wasteful number, since it uses less digits than its factorization.

1605406561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637559.

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

The square root of 1605406561 is about 40067.5250171507. The cubic root of 1605406561 is about 1170.9230208702.

The spelling of 1605406561 in words is "one billion, six hundred five million, four hundred six thousand, five hundred sixty-one".