1660520405 has 4 divisors (see below), whose sum is σ = 1992624492. Its totient is φ = 1328416320.

The previous prime is 1660520383. The next prime is 1660520413. The reversal of 1660520405 is 5040250661.

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 706390084 + 954130321 = 26578^2 + 30889^2 .

It is not a de Polignac number, because 1660520405 - 2⁸ = 1660520149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166052036 + ... + 166052045.

It is an arithmetic number, because the mean of its divisors is an integer number (498156123).

Almost surely, 2^1660520405 is an apocalyptic number.

It is an amenable number.

1660520405 is a deficient number, since it is larger than the sum of its proper divisors (332104087).

1660520405 is an equidigital number, since it uses as much as digits as its factorization.

1660520405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332104086.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 1660520405 is about 40749.4834936592. The cubic root of 1660520405 is about 1184.1718664579.

The spelling of 1660520405 in words is "one billion, six hundred sixty million, five hundred twenty thousand, four hundred five".