1605601621 has 8 divisors (see below), whose sum is σ = 1729728000. Its totient is φ = 1481563632.

The previous prime is 1605601619. The next prime is 1605601637. The reversal of 1605601621 is 1261065061.

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

It is a cyclic number.

It is not a de Polignac number, because 1605601621 - 2¹ = 1605601619 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1605601621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605601021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18396 + ... + 59578.

It is an arithmetic number, because the mean of its divisors is an integer number (216216000).

Almost surely, 2^1605601621 is an apocalyptic number.

It is an amenable number.

1605601621 is a deficient number, since it is larger than the sum of its proper divisors (124126379).

1605601621 is a wasteful number, since it uses less digits than its factorization.

1605601621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44195.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 1605601621 is about 40069.9590840819. The cubic root of 1605601621 is about 1170.9704420864.

Adding to 1605601621 its reverse (1261065061), we get a palindrome (2866666682).

The spelling of 1605601621 in words is "one billion, six hundred five million, six hundred one thousand, six hundred twenty-one".