1645358405 has 4 divisors (see below), whose sum is σ = 1974430092. Its totient is φ = 1316286720.

The previous prime is 1645358399. The next prime is 1645358417. The reversal of 1645358405 is 5048535461.

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 1224370081 + 420988324 = 34991^2 + 20518^2 .

It is not a de Polignac number, because 1645358405 - 2¹⁰ = 1645357381 is a prime.

It is a Duffinian number.

It is a Curzon 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, 164535836 + ... + 164535845.

It is an arithmetic number, because the mean of its divisors is an integer number (493607523).

Almost surely, 2^1645358405 is an apocalyptic number.

It is an amenable number.

1645358405 is a deficient number, since it is larger than the sum of its proper divisors (329071687).

1645358405 is an equidigital number, since it uses as much as digits as its factorization.

1645358405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329071686.

The product of its (nonzero) digits is 288000, while the sum is 41.

The square root of 1645358405 is about 40563.0177008565. The cubic root of 1645358405 is about 1180.5566666332.

The spelling of 1645358405 in words is "one billion, six hundred forty-five million, three hundred fifty-eight thousand, four hundred five".