1645381355 has 4 divisors (see below), whose sum is σ = 1974457632. Its totient is φ = 1316305080.

The previous prime is 1645381349. The next prime is 1645381357. The reversal of 1645381355 is 5531835461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5531835461 = 28949 ⋅191089.

It is a de Polignac number, because none of the positive numbers 2^k-1645381355 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645381357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164538131 + ... + 164538140.

It is an arithmetic number, because the mean of its divisors is an integer number (493614408).

Almost surely, 2^1645381355 is an apocalyptic number.

1645381355 is a deficient number, since it is larger than the sum of its proper divisors (329076277).

1645381355 is an equidigital number, since it uses as much as digits as its factorization.

1645381355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329076276.

The product of its digits is 216000, while the sum is 41.

The square root of 1645381355 is about 40563.3005930237. The cubic root of 1645381355 is about 1180.5621555385.

The spelling of 1645381355 in words is "one billion, six hundred forty-five million, three hundred eighty-one thousand, three hundred fifty-five".