1645379987 has 4 divisors (see below), whose sum is σ = 1645866336. Its totient is φ = 1644893640.

The previous prime is 1645379977. The next prime is 1645380017. The reversal of 1645379987 is 7899735461.

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 1645379987 - 2⁴ = 1645379971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645379927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238064 + ... + 244877.

It is an arithmetic number, because the mean of its divisors is an integer number (411466584).

Almost surely, 2^1645379987 is an apocalyptic number.

1645379987 is a deficient number, since it is larger than the sum of its proper divisors (486349).

1645379987 is an equidigital number, since it uses as much as digits as its factorization.

1645379987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486348.

The product of its digits is 11430720, while the sum is 59.

The square root of 1645379987 is about 40563.2837304871. The cubic root of 1645379987 is about 1180.5618283582.

The spelling of 1645379987 in words is "one billion, six hundred forty-five million, three hundred seventy-nine thousand, nine hundred eighty-seven".