1605260521651 has 4 divisors (see below), whose sum is σ = 1614872860272. Its totient is φ = 1595648183032.

The previous prime is 1605260521649. The next prime is 1605260521693. The reversal of 1605260521651 is 1561250625061.

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

It is a cyclic number.

It is not a de Polignac number, because 1605260521651 - 2¹ = 1605260521649 is a prime.

It is a super-2 number, since 2×1605260521651² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1605260561651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4806169060 + ... + 4806169393.

It is an arithmetic number, because the mean of its divisors is an integer number (403718215068).

Almost surely, 2^{1605260521651} is an apocalyptic number.

1605260521651 is a deficient number, since it is larger than the sum of its proper divisors (9612338621).

1605260521651 is an equidigital number, since it uses as much as digits as its factorization.

1605260521651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9612338620.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 1605260521651 in words is "one trillion, six hundred five billion, two hundred sixty million, five hundred twenty-one thousand, six hundred fifty-one".